Deflectable intravascular filter

ABSTRACT

Single filter and multi-filter endolumenal methods and systems for filtering fluids within the body. In some embodiments a blood filtering system captures and removes particulates dislodged or generated during a surgical procedure and circulating in a patient&#39;s vasculature. In some embodiments a filter system protects the cerebral vasculature during a cardiac valve repair or replacement procedure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit under 35 U.S.C. §119(e) ofU.S. Provisional Application No. 61/428,653, filed Dec. 30, 2010; U.S.Provisional Application No. 61/493,447, filed Jun. 4, 2011; U.S.Provisional Application No. 61/550,889, filed Oct. 24, 2011; and U.S.Provisional Application No. 61/556,142, filed Nov. 4, 2011, the entirecontents of which are hereby incorporated by reference and should beconsidered a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

In general, the disclosure relates to methods and apparatuses forfiltering blood. The filtration systems can be catheter-based forinsertion into a patient's vascular system.

2. Description of the Related Art

Thromboembolic disorders, such as stroke, pulmonary embolism, peripheralthrombosis, atherosclerosis, and the like, affect many people. Thesedisorders are a major cause of morbidity and mortality in the UnitedStates and throughout the world. Thromboembolic events are characterizedby an occlusion of a blood vessel. The occlusion can be caused by a clotwhich is viscoelastic (jelly-like) and is comprised of platelets,fibrinogen, and other clotting proteins.

Percutaneous aortic valve replacement has been in development for sometime now and stroke rates related to this procedure are between four andtwenty percent. During catheter delivery and valve implantation plaqueor other material may be dislodged from the vasculature and may travelthrough the carotid circulation and into the brain. When an artery isoccluded by a clot or other embolic material, tissue ischemia (lack ofoxygen and nutrients) develops. The ischemia will progress to tissueinfarction (cell death) if the occlusion persists. Infarction does notdevelop or is greatly limited if the flow of blood is reestablishedrapidly. Failure to reestablish blood-flow can lead to the loss of limb,angina pectoris, myocardial infarction, stroke, or even death.

Occlusion of the venous circulation by thrombi leads to blood stasiswhich can cause numerous problems. The majority of pulmonary embolismsare caused by emboli that originate in the peripheral venous system.Reestablishing blood flow and removal of the thrombus is highlydesirable.

Techniques exist to reestablish blood flow in an occluded vessel. Onecommon surgical technique, an embolectomy, involves incising a bloodvessel and introducing a balloon-tipped device (such as a Fogartycatheter) to the location of the occlusion. The balloon is then inflatedat a point beyond the clot and used to translate the obstructingmaterial back to the point of incision. The obstructing material is thenremoved by the surgeon. While such surgical techniques have been useful,exposing a patient to surgery may be traumatic and is best avoided whenpossible. Additionally, the use of a Fogarty catheter may be problematicdue to the possible risk of damaging the interior lining of the vesselas the catheter is being withdrawn.

A common percutaneous technique is referred to as balloon angioplastywhere a balloon-tipped catheter is introduced into a blood vessel,typically through an introducing catheter. The balloon-tipped catheteris then advanced to the point of the occlusion and inflated in order todilate the stenosis. Balloon angioplasty is appropriate for treatingvessel stenosis but is generally not effective for treating acutethromboembolisms.

Another percutaneous technique is to place a microcatheter near the clotand infuse Streptokinase, Urokinase, or other thrombolytic agents todissolve the clot. Unfortunately, thrombolysis typically takes hours ordays to be successful. Additionally, thrombolytic agents can causehemorrhage and in many patients the agents cannot be used at all.

Another problematic area is the removal of foreign bodies. Foreignbodies introduced into the circulation can be fragments of catheters,pace-maker electrodes, guide wires, and erroneously placed embolicmaterial such as thrombogenic coils. Retrieval devices exist for theremoval of foreign bodies, some of which form a loop that can ensnarethe foreign material by decreasing the size of the diameter of the looparound the foreign body. The use of such removal devices can bedifficult and sometimes unsuccessful.

Moreover, systems heretofore disclosed in the art are generally limitedby size compatibility and the increase in vessel size as the emboli isdrawn out from the distal vascular occlusion location to a more proximallocation near the heart. If the embolectomy device is too large for thevessel it will not deploy correctly to capture the clot or foreign body,and if too small in diameter it cannot capture clots or foreign bodiesacross the entire cross section of the blood vessel. Additionally, ifthe embolectomy device is too small in retaining volume then as thedevice is retracted the excess material being removed can spill out andbe carried by flow back to occlude another vessel downstream.

Various thrombectomy and foreign matter removal devices have beendisclosed in the art. Such devices, however, have been found to havestructures which are either highly complex or lacking in sufficientretaining structure. Disadvantages associated with the devices havinghighly complex structure include difficulty in manufacturability as wellas difficulty in use in conjunction with microcatheters. Recentdevelopments in the removal device art features umbrella filter deviceshaving self folding capabilities. Typically, these filters fold into apleated condition, where the pleats extend radially and can obstructretraction of the device into the microcatheter sheathing.

Extraction systems are needed that can be easily and controllablydeployed into and retracted from the circulatory system for theeffective removal of clots and foreign bodies. There is also a need forsystems that can be used as temporary arterial or venous filters tocapture and remove thromboemboli generated during endovascularprocedures. The systems should also be able to be properly positioned inthe desired location. Additionally, due to difficult-to-access anatomysuch as the cerebral vasculature and the neurovasculature, the systemsshould have a small collapsed profile.

The risk of dislodging foreign bodies is also prevalent in certainsurgical procedures. It is therefore further desirable that such embolicapture and removal apparatuses are similarly useful with surgicalprocedures such as, without limitation, cardiac valve replacement,cardiac bypass grafting, cardiac reduction, or aortic replacement.

SUMMARY OF THE INVENTION

One aspect of the disclosure is a catheter-based endovascular system andmethod of use for filtering blood that captures and removes particlescaused as a result of a surgical or endovascular procedures. The methodand system include a first filter placed in a first vessel within thepatient's vascular system and a second filter placed in a second vesselwithin the patient's vascular system. In this manner, the level ofparticulate protection is thereby increased.

One aspect of the disclosure is an endovascular filtration system andmethod of filtering blood that protects the cerebral vasculature fromembolisms instigated or foreign bodies dislodged during a surgicalprocedure. In this aspect, the catheter-based filtration system isdisposed at a location in the patient's arterial system between the siteof the surgical procedure and the cerebral vasculature. Thecatheter-based filtration system is inserted and deployed at the site tocapture embolisms and other foreign bodies and prevent their travel tothe patient's cerebral vasculature so as to avoid or minimizethromboembolic disorders such as a stroke.

One aspect of the disclosure is an endovascular filtration system andmethod of filtering blood that provides embolic protection to thecerebral vasculature during a cardiac or cardiothoracic surgicalprocedure. According to this aspect, the filtration system is acatheter-based system provided with at least a first filter and a secondfilter. The first filter is positioned within the brachiocephalicartery, between the aorta and the right common carotid artery, with thesecond filter being positioned within the left common carotid artery.

One aspect of the disclosure is a catheter-based endovascular filtrationsystem including a first filter and a second filter, wherein the systemis inserted into the patient's right brachial or right radial artery.The system is then advanced through the patient's right subclavianartery and into the brachiocephalic artery. Alternately, the system maybe inserted directly into the right subclavian artery. At a positionwithin the brachiocephalic trunk between the aorta and the right commoncarotid artery, the catheter-based system is manipulated to deploy thefirst filter. The second filter is then advanced through or adjacent tothe deployed first filter into the aorta and then into the left commoncarotid artery. Once in position within the left common carotid arterythe catheter-based system is further actuated to deploy the secondfilter. After the surgical procedure is completed, the second filter andthe first filter are, respectively, collapsed and withdrawn from thearteries and the catheter-based filtration system is removed from thepatient's vasculature. In an alternate embodiment, either or both thefirst and second filters may be detached from the filtration system andleft inside the patient for a therapeutic period of time.

One aspect of the disclosure is a catheter-based filtration systemcomprising a handle, a first sheath, a first filter, a second sheath anda second filter. The first and second sheaths are independentlyactuatable. The handle can be a single or multiple section handle. Thefirst sheath is translatable relative to the first filter to enactdeployment of the first filter in a first vessel. The second sheath isarticulatable from a first configuration to one or more otherconfigurations. The extent of articulation applied to the second sheathis determined by the anatomy of a second vessel to which access is to begained. The second filter is advanced through the articulated secondsheath and into the vessel accessed by the second sheath and,thereafter, deployed in the second vessel. Actuation of the first sheathrelative to the first filter and articulation of the second filter isprovided via the handle. In some embodiments, the handle includes alocking mechanism configured to lock the first sheath relative to thesecond sheath. In certain embodiments, the handle also includes a distalflush port.

In some aspects of the disclosure, the second filter is carried on aguiding member having a guidewire lumen extending therethrough. Incertain aspects, the guiding member is a catheter shaft. A guidingmember having a guidewire lumen allows the user to precisely deliver thesecond filter by advancing the filter system over the guidewire. Theguiding member can be configured to have increased column strength toaid advancement of the second filter. In some aspects, the guidingmember includes a flexible portion to better position the second filterwithin the vessel.

In some aspects the first sheath is a proximal sheath, the first filteris a proximal filter, the second sheath is a distal sheath, and thesecond filter is a distal filter. The proximal sheath is provided with aproximal hub housed within and in sliding engagement with the handle.Movement of the proximal hub causes translation of the proximal sheathrelative to the proximal filter. The distal sheath includes a distalshaft section and a distal articulatable sheath section. A wire isprovided from the handle to the distal articulatable sheath section.Manipulation of the handle places tension on the wire causing the distalarticulatable sheath section to articulate from a first configuration toone or more other configurations. The articulatable distal sheath iscapable of rotation, translation, and deflection (both in a single planeand both partially in a first plane and partially in a second, differentplane). In some embodiments, the handle includes a locking mechanism toprevent the articulatable distal sheath from deviating from a desiredconfiguration. In certain embodiments, the locking mechanism may lockautomatically when the operator actuates a control or releases thehandle.

In some aspects the proximal filter and the distal filter are bothself-expanding. The proximal filter and the distal filter both maycomprise an oblique truncated cone shape. Movement of the proximalsheath relative to the proximal filter causes the proximal filter toexpand and deploy against the inside wall of a first vessel. The distalfilter is then advanced through or adjacent to the distal shaft anddistal articulatable sheath into expanding engagement against the innerwall of a second vessel. In some embodiments, a tethering member extendsfrom the proximal sheath to the proximal filter to help draw theproximal filter opening toward the first vessel wall.

Another aspect of the disclosure is a single filter embolic protectiondevice comprising a single filter device comprising a sheath, a filtershaft, and a filter assembly. In some aspects, the filter assembly isdesigned to accommodate a catheter-based device passing between thefilter and the vessel wall. In certain embodiments, the filter assemblymay include a channel, a gap, or an inflatable annulus. The filterassembly may also include one or more filter lobes. In anotherembodiment, the filter assembly may resemble an umbrella having aplurality of tines and a filter element connecting each tine. The filterassembly may alternatively include a plurality of overlapping filterportions, wherein a catheter may pass between a first filter portion anda second filter portion of the filter assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary prior art catheter being advancedthrough a portion of a subject's vasculature.

FIGS. 1A-1D illustrate an exemplary dual filter system.

FIGS. 1E and 1F illustrate exemplary proximal filters.

FIGS. 2A-2D illustrate an exemplary method of delivering and deploying adual filter system

FIGS. 3-5 illustrate a portion of an exemplary delivery procedure forpositioning a blood filter.

FIGS. 6A and 6B illustrate an exemplary embodiment of an articulatingdistal sheath.

FIGS. 7A-7C illustrate a portion of an exemplary filter system.

FIGS. 8A-8C illustrate an exemplary pull wire.

FIGS. 9A-9C show an exemplary embodiment of a distal sheath with slotsformed therein.

FIGS. 9D-9E show an exemplary embodiment of a distal sheath capable ofdeflecting in multiple directions.

FIGS. 9F and 9G illustrate exemplary guidewire lumen locations in thedistal sheath.

FIGS. 10A and 10B illustrate a portion of exemplary distal sheathadapted to be multi-directional.

FIGS. 11A-11E illustrate merely exemplary anatomical variations that canexist.

FIGS. 12A and 12B illustrate an exemplary curvature of a distal sheathto help position the distal filter properly in the left common carotidartery.

FIGS. 13A and 13B illustrate alternative distal sheath and distal shaftportions of an exemplary filter system.

FIG. 14 illustrates a portion of an exemplary system including a distalshaft and a distal sheath.

FIGS. 15A-15D illustrate alternative embodiments of the coupling of thedistal shaft and distal sheath.

FIG. 16 illustrates an exemplary embodiment of a filter system in whichthe distal sheath is biased to a curved configuration.

FIG. 17 illustrates a portion of an alternative filter system.

FIGS. 18A and 18B illustrate an exemplary proximal filter.

FIGS. 19A-19C, 20A-20B, 21, 22A-B illustrate exemplary proximal filters.

FIGS. 23A-23F illustrate exemplary distal filters.

FIGS. 24A-24C illustrate exemplary embodiments in which the systemincludes at least one distal filter positioning, or stabilizing, anchor.

FIGS. 25A-25D illustrate an exemplary embodiment of coupling a distalfilter to a docking wire inside of the subject.

FIGS. 26A-26G illustrate an exemplary method of preparing an exemplarydistal filter assembly for use.

FIGS. 27A and 27B illustrate an exemplary embodiment in which a guidingmember, secured to a distal filter before introduction into the subjectis loaded into an articulatable distal sheath.

FIGS. 28A-28E illustrate an exemplary distal filter assembly incollapsed and expanded configurations.

FIGS. 29A-29E illustrate a portion of an exemplary filter system with alower delivery and insertion profile.

FIGS. 30A and 30B illustrate a portion of an exemplary filter system.

FIGS. 31A-31C illustrate an exemplary over-the-wire routing system thatincludes a separate distal port for a dedicated guidewire.

FIGS. 32A-32E illustrate an exemplary routing system which includes arapid-exchange guidewire delivery.

FIGS. 33A-D illustrates a filter system which includes a tubular coremember.

FIGS. 34A-C illustrate a filter system with a flexible coupler.

FIGS. 35A-E illustrate alternate designs for a flexible coupler.

FIGS. 36A-C illustrate a method of using a tethering member.

FIGS. 36D-E illustrate attachment points for a tethering member.

FIGS. 37A-D illustrate multiple embodiments for a tethering member.

FIGS. 38A-D illustrate multiple embodiments for an aortic filterdesigned to form a seal around a catheter.

FIGS. 39A-C illustrate an aortic filter system having multiple aorticfilters.

FIGS. 40A-B exemplify multiple embodiments for an aortic filter.

FIGS. 41A-B illustrate an aortic filter having an inflatable annulus.

FIG. 42 illustrates a distal portion of an exemplary filter system.

FIGS. 43-46 illustrate exemplary control handles of the blood filtersystems.

FIGS. 47A-H illustrate cross-sectional portions of an exemplary controlhandle.

FIG. 48 depicts an alternative control handle with a rotary tipdeflection control.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Although certain preferred embodiments and examples are disclosed below,inventive subject matter extends beyond the specifically disclosedembodiments to other alternative embodiments and/or uses, and tomodifications and equivalents thereof. Thus, the scope of the claimsappended hereto is not limited by any of the particular embodimentsdescribed below. For example, in any method or process disclosed herein,the acts or operations of the method or process can be performed in anysuitable sequence and are not necessarily limited to any particulardisclosed sequence. Various operations can be described as multiplediscrete operations in turn, in a manner that can be helpful inunderstanding certain embodiments; however, the order of descriptionshould not be construed to imply that these operations are orderdependent. Additionally, the structures described herein can be embodiedas integrated components or as separate components. For purposes ofcomparing various embodiments, certain aspects and advantages of theseembodiments are described. Not necessarily all such aspects oradvantages are achieved by any particular embodiment. Thus, for example,various embodiments can be carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other aspects or advantages as can also be taughtor suggested herein.

The disclosure relates generally to intravascular blood filters used tocapture foreign particles. In some embodiments the blood filter is adual-filter system to trap foreign bodies to prevent them from travelinginto the subject's right and left common carotid arteries, while inother embodiments, the blood filter is a single filter system. Thefilter systems described herein can, however, be used to trap particlesin other blood vessels within a subject, and they can also be usedoutside of the vasculature. The systems described herein are generallyadapted to be delivered percutaneously to a target location within asubject, but they can be delivered in any suitable way, and need not belimited to minimally-invasive procedures.

Filter systems in accordance with the present invention can be utilizedto reduce the occurrence of emboli entering the cerebral circulation asa consequence of any of a variety of intravascular interventions,including, but not limited to, transcatheter aortic-valve implantation(TAVI), surgical valve repair or replacement, atrial fibrillationablation, cardiac bypass surgery, or transthoracic graft placementaround the aortic arch. For example, the present filter or filters maybe placed as described elsewhere herein prior to a minimally invasive oropen surgical repair or replacement of a heart valve, such as the mitralor aortic valve. The filter system may alternatively be placed prior tocardiac ablation such as ablation of the pulmonary vein to treat atrialfibrillation. Ablation may be accomplished using any of a variety ofenergy modalities, such as RF energy, cryo, microwave or ultrasound,delivered via a catheter having a distal end positioned within theheart. The present filter systems may alternatively be placed prior tocardiac bypass surgery, or prior to transthoracic graft placement aroundthe aortic arch, or any of a variety of other surgeries or interventionsthat are accompanied by a risk of cerebral embolization.

In one application, the filter systems described herein are used toprotect the cerebral vasculature against embolisms and other foreignbodies entering the bloodstream during a cardiac valve replacement orrepair procedure. To protect both the right common carotid artery andthe left common carotid artery during such procedures, the systemdescribed herein enters the aorta from the brachiocephalic artery. Oncein the aortic space, there is a need to immediately navigate a 180degree turn into the left common carotid artery. In gaining entry intothe aorta from the brachiocephalic artery, use of prior art catheterdevices 1 will tend to hug the outer edge of the vessel 2, as shown inFIG. 1. To then gain access to the left common carotid artery 3 withsuch prior art devices can be a difficult maneuver due to the closeproximity of the two vessels which may parallel one another, oftenwithin 1 cm of separation, as shown in, for example, FIGS. 1-5. Thissharp turn requires a very small radius and may tend to kink thecatheter reducing or eliminating a through lumen to advance accessoriessuch as guidewires, filters, stents, and other interventional tools. Thecatheter-based filter systems described herein can traverse this ratherabrupt essentially 180 degree turn to thereby deploy filters to protectboth the right and left common carotid arteries.

FIGS. 1A-1C illustrate an exemplary filter system having control handleportion 5 and filter system 10. In some embodiments, control handleportion 5 may include a distal flush port 4. Filter system 10 includesproximal sheath 12, proximal shaft 14 coupled to expandable proximalfilter 16, distal shaft 18 coupled to distal articulatable sheath 20,distal filter 22, and guiding member 24. FIG. 1B illustrates proximalfilter 16 and distal filter 22 in expanded configurations. FIG. 1Cillustrates the system in a delivery configuration, in which proximalfilter 16 (not seen in FIG. 1C) is in a collapsed configurationconstrained within proximal sheath 12, while distal filter 22 is in acollapsed configuration constrained within distal articulatable sheath20.

FIG. 1D is a sectional view of partial system 10 from FIG. 1C. Proximalshaft 14 is co-axial with proximal sheath 12, and proximal region 26 ofproximal filter 16 is secured to proximal shaft 14. In its collapsedconfiguration, proximal filter 16 is disposed within proximal sheath 12and is disposed distally relative to proximal shaft 14. Proximal sheath12 is axially (distally and proximally) movable relative to proximalshaft 14 and proximal filter 16. System 10 also includes distal sheath20 secured to a distal region of distal shaft 18. Distal shaft 18 isco-axial with proximal shaft 14 and proximal sheath 12. Distal sheath 20and distal shaft 18, secured to one another, are axially movablerelative to proximal sheath 12, proximal shaft 14 and proximal filter16. System 10 also includes distal filter 22 carried by guiding member24. In FIG. 1D distal filter 22 is in a collapsed configuration withindistal sheath 22. Guiding member 24 is coaxial with distal sheath 20 anddistal shaft 18 as well as proximal sheath 12 and proximal shaft 14.Guiding member 24 is axially movable relative to distal sheath 20 anddistal shaft 18 as well as proximal sheath 12 and proximal shaft 14.Proximal sheath 12, distal sheath 20, and guiding member 24 are eachadapted to be independently moved axially relative to one other. Thatis, proximal sheath 12, distal sheath 20, and guiding member 24 areadapted for independent axial translation relative to each of the othertwo components.

In the embodiments in FIGS. 1A-1F, proximal filter 16 includes supportelement or frame 15 and filter element 17, while distal filter 22includes support element 21 and filter element 23. The support elementsgenerally provide expansion support to the filter elements in theirrespective expanded configurations, while the filter elements areadapted to filter fluid, such as blood, and trap particles flowingtherethrough. The expansion supports are adapted to engage the wall ofthe lumen in which they are expanded. The filter elements have porestherein that are sized to allow the blood to flow therethrough, but aresmall enough to prevent unwanted foreign particles from passingtherethrough. The foreign particles are therefore trapped by and withinthe filter elements.

In one embodiment, filter element 17 is formed of a polyurethane filmmounted to frame 15, as shown in FIGS. 1E and 1F. Film element 17 canmeasure about 0.0001 inches to about 0.1 inches in thickness. In someembodiments, the film thickness measures between 0.005 and 0.05, orbetween 0.015 and 0.025. In some situations, it may be desirable to havea filter with a thickness less than 0.0001 or greater than 0.1 inches.Other polymers may also be used to form the filter element, in the formof a perforated sheet or woven or braided membranes. Thin membranes orwoven filament filter elements may alternatively comprise metal or metalalloys, such as nitinol, stainless steel, etc.

Filter element 17 has through holes 27 to allow fluid to pass and willresist the passage of the embolic material within the fluid. These holescan be circular, square, triangular or other geometric shapes. In theembodiment as shown in FIG. 1E, an equilateral triangular shape wouldrestrict a part larger than an inscribed circle but have an area forfluid flow nearly twice as large making the shape more efficient infiltration verses fluid volume. It is understood that similar shapessuch as squares and slots would provide a similar geometric advantage.In certain embodiments, the filter holes are laser drilled into thefilter membrane, but other methods can be used to achieve a similarresult. In some embodiments filter holes 27 are between about 1 micronand 1000 microns (1 mm). In certain embodiments, the hole size isbetween 1 micron and 500 microns. In other embodiments, the hole size isbetween 50 microns and 150 microns. However, the hole size can belarger, depending on the location of the filter within the subject andthe type of particulate sought to be trapped in the filter.

In several embodiments, frame element 15 can be constructed of a shapememory material such as Nitinol, or other materials such as stainlesssteel or cobalt super alloy (MP35N for example) that have suitablematerial properties. Frame element 15 could take the form of a roundwire or could also be of a rectangular or elliptical shape to preserve asmaller delivery profile. In one such embodiment, frame element 15comprises Nitinol wire where the hoop is created from a straight pieceof wire and shape set into a frame where two straight legs runlongitudinally along the delivery system and create a circular distalportion onto which the filter film will be mounted. The circular or loopportion may include a radiopaque marker such as a small coil of gold,platinum iridium, or other radiopaque marker for visualization underfluoroscopy. In other embodiments, the frame element may not comprise ahoop, but include a spinal element disposed across a longitudinal lengthof the filter element. In still other embodiments, the filter elementmay not include a frame element.

The shape of the filter opening or frame elements 15, 17 may take acircular shape when viewed axially or other shape that apposes thevessel wall. In some embodiments, such as those illustrated in FIGS. 1E,1F and 25D, the shape of frame element 15 and filter element 17 are ofan oblique truncated cone having a non-uniform or unequal length aroundand along the length of the conical filter 16. In such a configuration,much like a windsock, the filter 16 would have a larger opening(upstream) diameter and a reduced ending (downstream) diameter. Theunconstrained, fully expanded filter diameter can measure between 3 mmand 30 mm, but in some embodiments, the diameter may be less than 3 mmor greater than 30 mm. In some embodiments, the diameter may rangebetween 10-25 mm or between 15-20 mm. The length of the filter may rangebetween 10 mm and 50 mm, but the length of the filter may be less than10 mm or greater than 50 mm. In some embodiments, the length may rangebetween 10 mm and 30 mm or between 30 mm and 50 mm. In one embodiment,the diameter of the filter opening could measure about 15-20 mm indiameter and have a length of about 30-50 mm. A selection of differentfilter sizes would allow treatment of a selection of patients havingdifferent vessel sizes.

In some embodiments the material of the filter element is a smoothand/or textured surface that is folded or contracted into a smalldelivery catheter by means of tension or compression into a lumen. Areinforcement fabric 29, as shown in FIG. 1F, may be added to orembedded in the filter to accommodate stresses placed on the filtermaterial by means of the tension or compression applied. This will alsoreduce the stretching that may occur during delivery and retraction offilter element 17. This reinforcement material 29 could be a polymer ormetallic weave to add additional localized strength. This material couldbe imbedded into the polyurethane film to reduce its thickness. In oneparticular embodiment, this imbedded material could be a polyester weavemounted to a portion of the filter near the longitudinal frame elementswhere the tensile forces act upon the frame and filter material toexpose and retract the filter from its delivery system. In someembodiments, the film measures between 0.0005 and 0.05, between 0.0025and 0.025, or between 0.0015 and 0.0025 inches thick. In certainembodiments, the thickness is between 0.015 and 0.025 inches. In somesituations, it may be desirable to have a filter with a thickness lessthan 0.0001 or greater than 0.1 inches. In some embodiments, thereinforcement fabric has a pore size between about 1 micron and about1000 microns. In certain embodiments, the pore size is between about 50microns and about 150 microns. While such an embodiment of the filterelements has been described for convenience with reference to proximalfilter element 17, it is understood that distal filter element 23 couldsimilarly take such form or forms.

As shown in FIG. 1B, proximal filter 16 has a generally distally-facingopening 13, and distal filter 22 has a generally proximally-facingopening 19. The filters can be thought of as facing opposite directions.As described in more detail below, the distal sheath is adapted to besteered, or bent, relative to the proximal sheath and the proximalfilter. As the distal sheath is steered, the relative directions inwhich the openings face will be adjusted. Regardless of the degree towhich the distal sheath is steered, the filters are still considered tohaving openings facing opposite directions. For example, the distalsheath could be steered to have a 180 degree bend, in which case thefilters would have openings facing in substantially the same direction.The directions of the filter openings are therefore described if thesystem were to assume a substantially straightened configuration, anexample of which is shown in FIG. 1B. Proximal filter element 17 tapersdown in the proximal direction from support element 15, while distalfilter element 23 tapers down in the distal direction from supportelement 21. A fluid, such as blood, flows through the opening and passesthrough the pores in the filter elements, while the filter elements areadapted to trap foreign particles therein and prevent their passage to alocation downstream to the filters.

In several embodiments, the filters are secured to separate systemcomponents. In the embodiment in FIGS. 1A-1D, for example, proximalfilter 16 is secured to proximal shaft 14, while distal filter 22 issecured to guiding member 24. In FIGS. 1A-1D, the filters are secured toindependently-actuatable components. This allows the filters to beindependently positioned and controlled. Additionally, the filters arecollapsed within two different tubular members in their collapsedconfigurations. In the embodiment in FIGS. 1A-1D, for example, proximalfilter 16 is collapsed within proximal sheath 12, while distal filter 22is collapsed within distal sheath 20. In the system's deliveryconfiguration, the filters are axially-spaced from one another; however,in an alternative embodiment, the filters may be positioned such that afirst filter is located within a second filter. For example, in FIG. 1D,distal filter 22 is distally-spaced relative to proximal filter 16.

In some embodiments the distal sheath and the proximal sheath havesubstantially the same outer diameter (see, e.g., FIGS. 1C and 1D). Whenthe filters are collapsed within the sheaths, the sheath portion of thesystem therefore has a substantially constant outer diameter, which canease the delivery of the system through the patient's body and increasethe safety of the delivery. In FIG. 1D, distal and proximal sheaths 20and 12 have substantially the same outer diameter, both of which havelarger outer diameters than the proximal shaft 14. Proximal shaft 14 hasa larger outer diameter than distal shaft 18, wherein distal shaft 18 isdisposed within proximal shaft 14. Guiding member 24 has a smallerdiameter than distal shaft 18. In some embodiments the proximal anddistal sheaths have an outer diameter between 3 French (F) and 14 F. Incertain embodiments, the outer diameter is between 4 F and 8 F. In stillother embodiments, the outer diameter is between 4 F and 6 F. In someembodiments the sheaths have different outer diameters. For example, theproximal sheath can have a size of 6 F, while the distal sheath has asize of 5 F. In an alternate embodiment the proximal sheath is 5 F andthe distal sheath is 4 F. A distal sheath with a smaller outer diameterthan the proximal sheath reduces the delivery profile of the system andcan ease delivery. In some methods of use, the filter system is advancedinto the subject through an incision made in the subject's right radialartery. In a variety of medical procedures a medical instrument isadvanced through a subject's femoral artery, which is larger than theright radial artery. A delivery catheter used in femoral artery accessprocedures has a larger outer diameter than would be allowed in a filtersystem advanced through a radial artery. Additionally, in some uses thefilter system is advanced from the right radial artery into the aortavia the brachiocephalic trunk. The radial artery has the smallestdiameter of the vessels through which the system is advanced. The radialartery therefore limits the size of the system that can be advanced intothe subject when the radial artery is the access point. The outerdiameters of the systems described herein, when advanced into thesubject via a radial artery, are therefore smaller than the outerdiameters of the guiding catheters (or sheaths) typically used whenaccess is gained via a femoral artery.

FIG. 6A illustrates a portion of a filter delivery system in a deliveryconfiguration. The system's delivery configuration generally refers tothe configuration when both filters are in collapsed configurationswithin the system. FIG. 6B illustrates that the distal articulatingsheath is independently movable with 3 degrees of freedom relative tothe proximal sheath and proximal filter. In FIG. 6A, proximal sheath 60and distal sheath 62 are coupled together at coupling 61. Coupling 61can be a variety of mechanisms to couple proximal sheath 60 to distalsheath 62. For example, coupling 61 can be an interference fit, afriction fit, a spline fitting, end to end butt fit or any other type ofsuitable coupling between the two sheaths. When coupled together, asshown in FIG. 6A, the components shown in FIG. 6B move as a unit. Forexample, proximal sheath 60, proximal shaft 64, proximal filter 66,distal shaft 68, and the distal filter (not shown but within distalsheath 62) will rotate and translate axially (in the proximal or distaldirection) as a unit. When proximal sheath 60 is retracted to allowproximal filter 66 to expand, as shown in FIG. 6B, distal sheath 62 canbe independently rotated (“R”), steered (“S”), or translated axially(“T”) (either in the proximal “P” direction or distal “D” direction).The distal sheath therefore has 3 independent degrees of freedom: axialtranslation, rotation, and steering. The adaptation to have 3independent degrees of freedom is advantageous when positioning thedistal sheath in a target location, details of which are describedbelow.

FIGS. 2A-2D illustrate a merely exemplary embodiment of a method ofusing any of the filter systems described herein. System 10 from FIGS.1A-1D is shown in the embodiment in FIGS. 2A-2D. System 10 is advancedinto the subject's right radial artery through an incision in the rightarm. The system is advanced through the right subclavian artery and intothe brachiocephalic trunk 11, and a portion of the system is positionedwithin aorta 9 as can be seen in FIG. 2A (although that which is shownin FIG. 2A is not intended to be limiting).

Proximal sheath 12 is retracted proximally to allow proximal filtersupport element 15 to expand to an expanded configuration against thewall of the brachiocephalic trunk 11, as is shown in FIG. 2B. Proximalfilter element 17 is secured either directly or indirectly to supportelement 15, and is therefore reconfigured to the configuration shown inFIG. 2B. The position of distal sheath 20 can be substantiallymaintained while proximal sheath 12 is retracted proximally. Onceexpanded, the proximal filter filters blood traveling through thebrachiocephalic artery 11, and therefore filters blood traveling intothe right common carotid artery 7. The expanded proximal filter istherefore in position to prevent foreign particles from traveling intothe right common carotid artery 7 and into the cerebral vasculature.

Distal sheath 20 is then steered, or bent, and distal end 26 of distalsheath 20 is advanced into the left common carotid artery 13, as shownin FIG. 2C. Guiding member 24 is thereafter advanced distally relativeto distal sheath 20, allowing the distal support element to expand froma collapsed configuration to a deployed configuration against the wallof the left common carotid artery 13 as shown in FIG. 2D. The distalfilter element is also reconfigured into the configuration shown in FIG.2D. Once expanded, the distal filter filters blood traveling through theleft common carotid artery 13. The distal filter is therefore inposition to trap foreign particles and prevent them from traveling intothe cerebral vasculature.

In several embodiments, the proximal and distal filter elements or frameelements comprise elastic or shape memory material causing the filtersto expand as they exit their respective sheaths. In other embodiments,mechanical or hydraulic mechanisms may be used to expand each filterelement. Once the filters are in place and expanded, an optional medicalprocedure can then take place, such as a valvuloplasty and/orreplacement heart valve procedure. Any plaque or thrombus dislodgedduring the heart valve procedure that enters into the brachiocephalictrunk or the left common carotid artery will be trapped in the filters.

The filter system can thereafter be removed from the subject (or at anypoint in the procedure). In an exemplary embodiment, distal filter 22 isfirst retrieved back within distal sheath 20 to the collapsedconfiguration. To do this, guiding member 24 is retracted proximallyrelative to distal sheath 20. This relative axial movement causes distalsheath 20 to engage strut 28 and begin to move strut 28 towards guidingmember 24. Support element 21, which is coupled to strut 28, begins tocollapse upon the collapse of strut 28. Filter element 23 thereforebegins to collapse as well. Continued relative axial movement betweenguiding member 24 and distal sheath 20 continues to collapse strut 28,support element 21, and filter element 23 until distal filter 22 isretrieved and re-collapsed back within distal sheath 20 (as shown inFIG. 2C). Any foreign particles trapped within distal filter element 23are contained therein as the distal filter is re-sheathed. Distal sheath20 is then steered into the configuration shown in FIG. 2B, and proximalsheath is then advanced distally relative to proximal filter 16. Thiscauses proximal filter 16 to collapse around distal shaft 18, trappingany particles within the collapsed proximal filter. Proximal sheath 12continues to be moved distally towards distal sheath 20 until in theposition shown in FIG. 2A. The entire system 10 can then be removed fromthe subject.

In any of the embodiments mentioned herein, the filter or filters mayalternatively be detached from the delivery catheter, and the deliverycatheter removed leaving the filter behind. The filter or filters can beleft in place permanently, or retrieved by snaring it with a retrievalcatheter following a post procedure treatment period of time.Alternatively, the filters may remain attached to the catheter, and thecatheter may be left in place post procedure for the treatment period oftime. That treatment period may be at least one day, one week, threeweeks, five weeks or more, depending upon the clinical circumstances.Patients with an indwelling filter or filters may be administered any ofa variety of thrombolytic or anticoagulant therapies, including tissueplasminogen activator, streptokinase, coumadin, heparin and others knownin the art.

An exemplary advantage of the systems described herein is that thedelivery and retrieval system are integrated into the same catheter thatstays in place during the procedure. Unloading and loading of differentcatheters, sheaths, or other components is therefore unnecessary. Havinga system that performs both delivery and retrieval functions alsoreduces procedural complexity, time, and fluoroscopy exposure time. Inaddition, only a minimal portion of the catheter is in the aortic arch,thus greatly reducing the change of interference with other catheters.

FIGS. 7A-7B illustrate a perspective view and sectional view,respectively, of a portion of an exemplary filter system. The systemincludes distal shaft 30 and distal articulatable sheath 34, coupled viacoupler 32. FIG. 7B shows the sectional view of plane A. Distal sheath34 includes steering element 38 extending down the length of the sheathand within the sheath, which is shown as a pull wire. The pull wire canbe, for example without limitation, stainless steel, tungsten, alloys ofcobalt such as MP35N®, or any type of cable, either comprised of asingle strand or two or more strands. Distal sheath 34 also includesspine element 36, which is shown extending down the length of the sheathon substantially the opposite side of the sheath from steering element38. Spine element 36 can be, for example without limitation, a ribbon orround wire. Spine element 36 can be made from, for example, stainlesssteel or Nitinol. Spine element 36 resists axial expansion orcompression of articulatable sheath 34 upon the application of anactuating axial pull or push force applied to steering element 38,allowing sheath 34 to be deflected toward configuration 40, as shown inphantom in FIG. 7A. FIG. 7C shows an alternative embodiment in whichdistal sheath 33 has a non-circular cross section. Also shown are spineelement 35 and steering element 37.

FIGS. 8A-8C illustrate views of exemplary pull wire 42 that can beincorporated into any distal sheaths described herein. Plane B in FIG.8B shows a substantially circular cross-sectional shape of pull wire 42in a proximal portion 44 of the pull wire, while plane C in FIG. 8Cshows a flattened cross-sectional shape of distal portion 46. Distalportion 46 has a greater width than height. The flattenedcross-sectional shape of distal portion 46 provides for an improvedprofile, flexibility, and resistance to plastic deformation, whichprovides for improved straightening.

FIGS. 9A-C show an alternative embodiment of distal sheath 48 thatincludes slots 50 formed therein. The slots can be formed by, forexample, grinding, laser cutting or other suitable material removal fromdistal sheath 48. Alternatively, the slots can be the openings betweenspaced apart coils or filars of a spring. The characteristics of theslots can be varied to control the properties of the distal sheath. Forexample, the pitch, width, depth, etc., of the slots can be modified tocontrol the flexibility, compressibility, torsional responsiveness,etc., of distal sheath 48. More specifically, the distal sheath 48 canbe formed from a length of stainless steel hypotubing. Transverse slots50 are preferably formed on one side of the hypotubing, leaving anopposing spine which provides column strength to avoid axial compressionor expansion upon application of an axial force to the pull wire andalso limits deflection to a desired single plane or predeterminedplanes.

FIG. 9B shows a further embodiment of the distal sheath in greaterdetail. In this embodiment distal sheath 48 includes a first proximalarticulatable hypotube section 49. Articulatable hypotube section 49 isfixed to distal shaft 30 (not shown in FIG. 9A). A second distalarticulatable section 51 is secured to first proximal section 49. Pullwire 38 extends from the handle through distal shaft section 49 and isaffixed to a distal portion of distal shaft portion 51. This embodimentallows for initial curvature of distal sheath proximal section 49 in afirst direction such as away from the outer vessel wall in response toproximal retraction of the pull wire 38. Distal sheath distal section 51is then articulated to a second curvature in a second, oppositedirection. This second curvature of distal shaft section 51 isadjustable based upon tension or compression loading of the sheathsection by pull wire 38. Alternatively, a first pull wire can beattached at a distal portion of section 49 and a second pull wire can beattached at a distal portion of section 51 to allow independentdeflection of the two deflection sections.

As shown in FIG. 9B, pull wire 38 in a single pull wire embodimentcrosses to an opposite side of the inner lumen defined by sections 49and 51 from the slots 50 as it transitions from the first distal sheathproximal section 49 to second distal sheath distal section 51. As bestshown in FIG. 9C, distal sheath proximal section 49 would articulatefirst to initialize a first curve, concave in a first direction as theslots 50 compress in response to proximal retraction of the pull wire38. As the tension on pull wire 38 is increased and the slots bottomout, distal sheath distal section 51 begins to form a second curveconcave in a second direction opposite to the direction of the firstcurve, due to pull wire 38 crossing the inner diameter of the lumenthrough distal sheath sections 49 and 51. As can be seen in FIG. 9C, asit nears and comes to the maximum extent of its articulation, distalsheath distal section 51 can take the form of a shepherd's staff orcrook.

Distal sheath proximal section 49 could take the form of a tubularslotted element or a pre-shaped curve that utilizes a memory materialsuch as Nitinol or any other material exhibiting suitable properties. Insome embodiments outer diameter of distal sheath proximal section 49 isbetween 0.02 inches and 0.2 inches. In certain embodiments, the outerdiameter is between 0.05 inches and 0.1 inches, or between 0.06 inchesand 0.075 inches. In some embodiments, the inner diameter of distalsheath proximal section 49 is between 0.02 inches and 0.2 inches. Incertain embodiments, the inner diameter is between 0.03 inches and 0.08inches or between 0.05 inches and 0.07 inches. In several embodiments,the length of distal sheath proximal section 49 may measures between 0.1inches and 2.5 inches. In some embodiments, the length of distal sheathproximal section 49 may measure between about 0.50 inches and 1 inch orbetween 0.6 inches and 0.8 inches. In certain embodiments, the length ofdistal sheath proximal section 49 may be longer than 2.5 inches. It isunderstood that these sizes and proportions will vary depending on thespecific application and those listed herein are not intended to belimiting. Transverse slots 50 can measure from about 0.002 inches toabout 0.020 inches in width (measured in the axial direction) dependingon the specific application and the degree of curvature desired. In someembodiments the slots can measure less than 0.002 inches or greater than0.02 inches. In certain embodiments, the slots 50 can measure about0.002 inches to 0.01 inches or between 0.006 and 0.01 inches.

The curvature of proximal section 49 may be varied from about 0 degreesto 90 degrees or more depending on the width and number of the slots 50.In several embodiments, the maximum degree of deflection ranges fromabout 15 degrees to about 75 degrees, from about 45 degrees to about 60degrees. Commencement of deflection of distal section 51 can occur priorto, simultaneously with or following commencement of deflection ofproximal section 49 based upon the relative stiffness of the sections orconfiguration of the pull wire as will be apparent to those of skill inthe art.

The distal sheath is configured such that the maximum net curvaturebetween the primary axis of the catheter prior to any deflection and thedistal tip axis is between about 90 and about 220 degrees. In otherembodiments, the maximum deflection is between about 120 degrees andabout 200 degrees, or between about 150 degrees and about 180 degrees.When the distal sheath is in its curved configuration, with a netdeflection from the primary axis of at least about 150 degrees, thelateral distance between the primary axis and the distal tip ranges fromabout 5 mm to about 15 mm.

The position of at least a second group of slots 50 may also berotationally displaced about the axis of the tube with respect to afirst group of slots to allow a first portion of the distal sheath tobend in a first plane and a second portion of the distal sheath to bendout-of-plane to access more complex anatomy as shown in FIGS. 9D and 9E.The second set of slots 50 may be displaced circumferentially from thefirst set of slots by about 5 degrees to about 90 degrees. In certainembodiments, the slots are displaced from about 15 to 60 degrees or fromabout 20 to about 40 degrees. The curvature of the out of plane curvemay vary from about 20 degrees to about 75 degrees, but in someembodiments, the out of plane curvature may be less than 20 degrees orgreater than 75 degrees. In several embodiments, the curvature of theout of plane curve is from about 20 degrees to 40 degrees, from about 30degrees to about 50 degrees, from about 40 degrees to about 60 degrees,or from about 50 degrees to 75 degrees. Alternatively, this out-of-planebend could be achieved by prebending the tube after laser cutting theslots to create a bias or by any other method which would create a bias.The shape could also be multi-plane or bidirectional where the tubewould bend in multiple directions within the same section of laser cuttube.

In several embodiments, distal sheath distal section 51 is a selectablecurve based upon the anatomy and vessel location relative to oneanother. This section 51 could also be a portion of the laser cutelement or a separate construction where a flat ribbon braid could beutilized. It may also include a stiffening element or bias ribbon toresist permanent deformation. In one embodiment it would have amultitude of flat ribbons staggered in length to create a constantradius of curvature under increased loading.

In some embodiments, distal sheath 34 incorporates a guidewire lumen 58through which a guidewire may pass as shown in FIG. 9F. Alternatively,in FIG. 9G, the guidewire lumen is coaxial with guiding member lumen 59.Removing the guidewire lumen from the wall of distal sheath 34 has theadded benefit of increasing the distal sheath luminal cross sectionalarea, reducing deployment and retrieval forces, and increasing thecapacity for debris within the distal sheath.

FIGS. 10A and 10B illustrate a portion of exemplary distal sheath 52that is adapted to be multi-directional, and is specifically shown to bebi-directional. Distal sheath 52 is adapted to be steered towards theconfigurations 53 and 54 shown in phantom in FIG. 10A. FIG. 10B is asectional view in plane D, showing spinal element 55 and first andsecond steering elements 56 disposed on either side of spinal element55. Steering elements 56 can be similar to steering element 38 shown inFIG. 7B. The steering elements can be disposed around the periphery ofdistal sheath at almost any location.

Incorporating steerable functionality into tubular devices is known inthe area of medical devices. Any such features can be incorporated intothe systems herein, and specifically into the articulatable distalsheaths.

In some embodiments the distal sheath includes radiopaque markers tovisualize the distal sheath under fluoroscopy. In some embodiments thedistal sheath has radiopaque markers at proximal and distal ends of thesheath to be able to visualize the ends of the sheath.

An exemplary advantage of the filter systems described herein is theability to safely and effectively position the distal sheath. In someuses, the proximal filter is deployed in a first bodily lumen, and thedistal filter is deployed in a second bodily lumen different than thefirst. For example, as shown in FIG. 2D, the proximal filter is deployedin the brachiocephalic trunk and the distal filter is deployed in a leftcommon carotid artery. While both vessels extend from the aortic arch,the position of the vessel openings along the aortic arch varies frompatient-to-patient. That is, the distance between the vessel openingscan vary from patient to patient. Additionally, the angle at which thevessels are disposed relative to the aorta can vary from patient topatient. Additionally, the vessels do not necessarily lie within acommon plane, although in many anatomical illustrations the vessels aretypically shown this way. For example, FIGS. 11A-11C illustrate merelyexemplary anatomical variations that can exist. FIG. 11A is a top view(i.e., in the superior-to-inferior direction) of aorta 70, showingrelative positions of brachiocephalic trunk opening 72, left commoncarotid artery opening 74, and left subclavian opening 76. FIG. 11B is aside sectional view of aortic 78 illustrating the relative angles atwhich brachiocephalic trunk 80, left common carotid artery 82, and leftsubclavian artery 84 can extend from aorta 78. FIG. 11C is a sidesectional view of aorta 86, showing vessel 88 extending from aorta 86 atan angle. Any or all of the vessels extending from aorta 86 could beoriented in this manner relative to the aorta. FIGS. 11D and 11Eillustrate that the angle of the turn required upon exiting thebrachiocephalic trunk 92/100 and entering the left common carotid artery94/102 can vary from patient to patient. Due to the patient-to-patientvariability between the position of the vessels and their relativeorientations, a greater amount of control of the distal sheath increasesthe likelihood that the distal filter will be positioned safely andeffectively. For example, a sheath that only has the ability toindependently perform one or two of rotation, steering, and axialtranslation may not be adequately adapted to properly and safelyposition the distal filter in the left common carotid artery. All threedegrees of independent motion as provided to the distal sheathsdescribed herein provide important clinical advantages. Typically, butwithout intending to be limiting, a subject's brachiocephalic trunk andleft carotid artery are spaced relatively close together and are eithersubstantially parallel or tightly acute (see, e.g., FIG. 11E).

FIGS. 12A and 12B illustrates an exemplary curvature of a distal sheathto help position the distal filter properly in the left common carotidartery. In FIGS. 12A and 12B, only a portion of the system is shown forclarity, but it can be assumed that a proximal filter is included, andin this example has been expanded in brachiocephalic trunk 111. Distalshaft 110 is coupled to steerable distal sheath 112. Distal sheath 112is steered into the configuration shown in FIG. 12B. The bend created indistal sheath 112, and therefore the relative orientations of distalsheath 112 and left common carotid artery 113, allow for the distalfilter to be advanced from distal sheath 112 into a proper position inleft common carotid 113. In contrast, the configuration of distal sheath114 shown in phantom in FIG. 12A illustrates how a certain bend createdin the distal sheath can orient the distal sheath in such a way that thedistal filter will be advanced directly into the wall of the left commoncarotid (depending on the subject's anatomy), which can injure the walland prevent the distal filter from being properly deployed. Depending onthe angulation, approach angle, spacing of the openings, etc., a generalU-shaped curve (shown in phantom in FIG. 12A) may not be optimal forsteering and accessing the left common carotid artery from thebrachiocephalic trunk.

In some embodiments the distal sheath is adapted to have a preset curvedconfiguration. The preset configuration can have, for example, a presetradius of curvature (or preset radii of curvature at different pointsalong the distal sheath). When the distal sheath is articulated to besteered to the preset configuration, continued articulation of thesteering element can change the configuration of the distal sheath untilis assumes the preset configuration. For example, the distal sheath cancomprise a slotted tube with a spine extending along the length of thedistal sheath. Upon actuation of the steering component, the distalsheath will bend until the portions of the distal sheath that define theslots engage, thus limiting the degree of the bend of the distal sheath.The curve can be preset into a configuration that increases thelikelihood that the distal filter will, when advanced from the distalsheath, be properly positioned within the left common carotid artery.

FIGS. 13A and 13B illustrate alternative distal sheath and distal shaftportions of an exemplary filter system. FIGS. 13A and 13B only showdistal shaft 120 and distal sheath 122 for clarity, but the system mayalso includes a proximal filter (not shown but has been deployed inbrachiocephalic trunk). The distal shaft/distal sheath combination has ageneral S-bend configuration, with distal shaft 120 including a firstbend 124 in a first direction, and distal sheath 122 configured toassume bend 126 in a second direction, wherein the first and secondbends form the general S-bend configuration. FIG. 13B shows distalsheath 122 pulled back in the proximal direction relative to theproximal filter to seat the curved distal sheath against the bend. Thisboth helps secure the distal sheath in place as well as reduces thecross sectional volume of the filter system that is disposed with theaorta. The distal shaft and distal sheath combination shown in FIGS. 13Aand 13B can be incorporated into any of the filter systems describedherein.

Exemplary embodiments of the delivery and deployment of a multi-filterembolic protection apparatus will now be described with reference toFIGS. 2A-2D, 13A, 13B, 14, 1, 3, 4 and 5. More particularly, thedelivery and deployment will be described with reference to placement ofthe filter system in the brachiocephalic and left common carotidarteries. The preferred access for the delivery of the multi-filtersystem 10 is from the right radial or right brachial artery, howeverother access locations such as the right subclavian artery are possible.The system is then advanced through the right subclavian artery to aposition within the brachiocephalic artery 11. At this point, proximalfilter 16 may be deployed within into expanding engagement with theinner lining of brachiocephalic artery 11. Alternatively, access to theleft common carotid could be gained prior to deployment of proximalfilter 16. Deployment of proximal filter 16 protects both thebrachiocephalic artery 11 and the right common carotid artery 7 againstemboli and other foreign bodies in the bloodstream.

Entry into the aortic space, as illustrated in FIG. 3, is thenaccomplished by further advancement of the system from thebrachiocephalic trunk. During this step, the filter system will tend tohug the outer portion of the brachiocephalic trunk as shown in FIG. 4.Initial tensioning of pull wire 38 causes distal sheath 48 to move thecatheter-based filter system off the wall of the brachiocephalic arteryjust before the ostium or entrance into the aorta, as shown in FIG. 4.As the catheter path will hug the outer wall of the brachial cephalicartery, a curve directed away from this outer wall will allow additionalspace for the distal portion of the distal sheath to curve into the leftcommon carotid artery, as shown in FIG. 5.

The width of slots 50 will determine the amount of bending allowed bythe tube when tension is applied via pull wire 38. For example, a narrowwidth slot would allow for limited bending where a wider slot wouldallow for additional bending due to the gap or space removed from thetube. As the bending is limited by the slot width, a fixed shape orcurve may be obtained when all slots are compressed and touching oneanother. Additional features such as chevrons may be cut into the tubeto increase the strength of the tube when compressed. Other means offorming slots could be obtained with conventional techniques such aschemical etching, welding of individual elements, mechanical forming,metal injection molding or other conventional methods.

Once in the aortic space, the distal sheath is further tensioned toadjust the curvature of the distal shaft distal section 51, as shown inFIG. 9B. The amount of deflection is determined by the operator of thesystem based on the particular patient anatomy.

Other techniques to bias a catheter could be external force applicationsto the catheter and the vessel wall such as a protruding ribbon or wirefrom the catheter wall to force the catheter shaft to a preferredposition within the vessel. Flaring a radial element from the cathetercentral axis could also position the catheter shaft to one side of thevessel wall. Yet another means would be to have a pull wire external tothe catheter shaft exiting at one portion and reattaching at a moredistal portion where a tension in the wire would bend or curve thecatheter at a variable rate in relation to the tension applied.

This multi-direction and variable curvature of the distal sheath allowsthe operator to easily direct the filter system, or more particularly,the distal sheath section thereof, into a select vessel such as the leftcommon carotid artery or the left innominate artery. Furthermore, thefilter system allows the operator to access the left common carotidartery without the need to separately place a guidewire in the leftcommon carotid artery. The clinical variations of these vessels are animportant reason for the operator to have a system that can accessdiffering locations and angulations between the vessels. The filtersystems described herein will provide the physician complete controlwhen attempting to access these vessels.

Once the distal sheath is oriented in the left common carotid, thehandle can be manipulated by pulling it and the filter system into thebifurcation leaving the aortic vessel clear of obstruction foradditional catheterizations, an example of which is shown in FIG. 12B.At this time, distal filter 22 can be advanced through proximal shaft 14and distal shaft 18 into expanding engagement with left common carotidartery 13.

FIG. 14 illustrates a portion of an exemplary system including distalshaft 130 and distal sheath 132. Distal sheath is adapted to be able tobe steered into what can be generally considered an S-bendconfiguration, a shepherd's staff configuration, or a crookconfiguration, comprised of first bend 131 and second bend 133 inopposite directions. Also shown is rotational orb 134, defined by theouter surface of the distal sheath as distal shaft 130 is rotated atleast 360 degrees in the direction of the arrows shown in FIG. 14. If atypical aorta is generally in the range from about 24 mm to about 30 mmin diameter, the radius of curvature and the first bend in the S-bendcan be specified to create a rotational orb that can reside within theaorta (as shown in FIG. 14), resulting in minimal interference with thevessel wall and at the same time potentially optimize access into theleft common carotid artery. In other distal sheath and/or distal shaftdesigns, such as the one shown in FIG. 12A, the rotational orb createdby the rotation of distal shaft 110 is significantly larger, increasingthe risk of interference with the vessel wall and potentially decreasingthe access into the left common carotid artery. In some embodiments, thediameter of the rotation orb for a distal sheath is less than about 25mm.

Referring back to FIG. 12A, distal sheath 112, in some embodiments,includes a non-steerable distal section 121, an intermediate steerablesection 119, and a proximal non-steerable section 117. When the distalsheath is actuated to be steered, only steerable portion 119 bends intoa different configuration. That is, the non-steerable portions retainsubstantially straight configurations. The distal non-steerable portionremains straight, which can allow the distal filter to be advanced intoa proper position in the left common carotid artery.

While FIG. 12A shows distal sheath 112 in a bent configuration, thedistal sheath is also positioned within the lumen of the aorta. In thisposition, the distal sheath can interfere with any other medical deviceor instrument that is being advanced through the aorta. For example, inaortic valve replacement procedures, delivery device 116, with areplacement aortic valve disposed therein, is delivered through theaorta as shown in FIG. 12B. If components of the filter system aredisposed within the aorta during this time, delivery device 116 and thefilter system can hit each other, potentially damaging either or bothsystems. The delivery device 116 can also dislodge one or both filtersif they are in the expanded configurations. The filter system canadditionally prevent the delivery device 116 from being advanced throughthe aorta. To reduce the risk of contact between delivery device 116 anddistal sheath 112, distal sheath 112 (and distal shaft 110) istranslated in the proximal direction relative to the proximal filter(which in this embodiment has already been expanded but is not shown),as is shown in FIG. 12B. Distal sheath 112 is pulled back until theinner curvature of distal sheath 112 is seated snugly with thevasculature 115 disposed between the brachiocephalic trunk 111 and theleft common carotid artery 113. This additional seating step helpssecure the distal sheath in place within the subject, as well asminimize the amount of the filter system present in the aortic arch.This additional seating step can be incorporated into any of the methodsdescribed herein, and is an exemplary advantage of having a distalsheath that has three degrees of independent motion relative to theproximal filter. The combination of independent rotation, steering, andaxial translation can be clinically significant to ensure the distalfilter is properly positioned in the lumen, as well as making sure thefilter system does not interfere with any other medical devices beingdelivered to the general area inside the subject.

An additional advantage of the filter systems herein is that the distalsheath, when in the position shown in FIG. 12B, will act as a protectionelement against any other medical instruments being delivered throughthe aorta (e.g., delivery device 116). Even if delivery device 116 wereadvanced such that it did engage distal sheath 112, distal sheath 112 isseated securely against tissue 115, thus preventing distal sheath 112from being dislodged. Additionally, distal sheath 112 is stronger than,for example, a wire positioned within the aorta, which can easily bedislodged when hit by delivery device 116.

FIGS. 15A-15D illustrate alternative embodiments of the coupling of thedistal shaft and distal sheath. In FIG. 15A distal shaft 140 is securedto distal sheath 142 by coupler 144. Shaft 140 has a low profile toallow for the collapse of the proximal filter (see FIG. 1C). Shaft 140also has column strength to allow for axial translation, has sufficienttorque transmission properties, and is flexible. The shaft can have asupport structure therein, such as braided stainless steel. For example,the shaft can comprise polyimide, Polyether ether ketone (PEEK), Nylon,Pebax, etc. FIG. 15B illustrates an alternative embodiment showingtubular element 146, distal shaft 148, and distal sheath 150. Tubularelement 146 can be a hypotube made from stainless steel, Nitinol, etc.FIG. 15C illustrates an exemplary embodiment that includes distal shaft152, traction member 154, and distal sheath 156. Traction member 154 iscoupled to shaft 152 and shaft 152 is disposed therein. Traction member154 couples to shaft 152 for torquebility, deliverability, anddeployment. Traction member 154 can be, for example without limitation,a soft silicone material, polyurethane, polyimide, or other materialhaving suitable properties. FIG. 15D shows an alternative embodiment inwhich the system includes bushing 162 disposed over distal shaft 158,wherein distal shaft 158 is adapted to rotate within bushing 162. Thesystem also includes stop 160 secured to distal shaft 158 tosubstantially maintain the axial position of bushing 162. When thesystem includes bushing 162, distal sheath 164 can be rotated relativeto the proximal sheath and the proximal filter when the distal sheathand proximal sheath are in the delivery configuration (see FIG. 1B).

FIG. 16 illustrates an exemplary embodiment of filter system 170 inwhich distal sheath 172 is biased to a curved configuration 174. Thebiased curved configuration is adapted to facilitate placement,delivery, and securing at least the distal filter. As shown, the distalsheath is biased to a configuration that positions the distal end of thedistal sheath towards the left common carotid artery.

FIG. 17 illustrates a portion of an exemplary filter system and itsmethod of use. FIG. 17 shows a system and portion of deployment similarto that shown in FIG. 2D, but distal sheath 182 has been retractedproximally relative to guiding member 190 and distal filter 186. Distalsheath 182 has been retracted substantially from the aortic arch and issubstantially disposed with the brachiocephalic trunk. Guiding member190 can have preset curve 188 adapted to closely mimic the anatomicalcurve between the brachiocephalic trunk and the left common carotidartery, thus minimizing the amount of the system that is disposed withinthe aorta. As shown, distal sheath 182 has been retracted proximallyrelative to proximal filter 180.

FIG. 18A is a perspective view of a portion of an exemplary embodimentof a filter system, while FIG. 18B is a close-up view of a portion ofthe system shown in FIG. 18A. The distal sheath and the distal filterare not shown in FIGS. 18A and 18B for clarity. The system includesproximal filter 200 coupled to proximal shaft 202, and push rod 206coupled to proximal shaft 202. A portion of proximal sheath 204 is shownin FIG. 18A in a retracted position, allowing proximal filter 200 toexpand to an expanded configuration. Only a portion of proximal sheath204 is shown, but it generally extends proximally similar to push rod206. The proximal end of proximal shaft 202 is beveled and defines anaspiration lumen 216, which is adapted to receive an aspirator (notshown) to apply a vacuum to aspirate debris captured within distallyfacing proximal filter 200. Push rod 206 extends proximally withinproximal sheath 204 and is coupled to an actuation system outside of thesubject, examples of which are described below. Push rod 206 takes upless space inside proximal sheath 204 than proximal shaft 202, providinga lower profile.

The system also includes proximal seal 214 disposed on the outer surfaceof proximal shaft 202 and adapted to engage the inner surface of theproximal sheath. Proximal seal 214 prevents bodily fluids, such asblood, from entering the space between proximal sheath 204 and proximalshaft 202, thus preventing bodily fluids from passing proximally intothe filter system. The proximal seal can be, for example withoutlimitation, a molded polymer. The proximal seal can also be machined aspart of the proximal shaft, such that they are not considered twoseparate components.

In some specific embodiments the push rod is between 0.001 inches and0.05 inches in diameter. In some embodiments, the diameter is between0.01 inches and 0.025 inches in diameter. The pushrod can be constructedfrom any number of polymeric or metal materials, such as stainlesssteel. The proximal shaft can be, for example without limitation, anextruded or molded plastic, a hypotube (e.g., stainless steel), machinedplastic, metal, etc.

Proximal filter 200 includes filter material 208, which comprises poresadapted to allow blood to pass therethrough, while debris does not passthrough the pores and is captured within the filter material. Proximalfilter 200 also includes strut 210 that extends from proximal shaft 202to expansion support 212. Expansion support 212 has a generally annularshape but that is not intended to be limiting. Proximal filter 200 alsohas a leading portion 220 and a trailing portion 222. Leading portion220 generally extends further distally than trailing portion 222 to givefilter 200 a generally canted configuration relative to the proximalshaft. The canted design provides for decreased radial stiffness and abetter collapsed profile. Strut 210 and expansion support 212 generallyprovide support for filter 200 when in the expanded configuration, asshown in FIG. 18A.

FIGS. 19A-19C illustrate exemplary embodiments of proximal filters andproximal shafts that can be incorporated into any of the systems herein.In FIG. 19A, filter 230 has flared end 232 for improved filter-wallopposition. FIG. 19B shows proximal shaft 244 substantially co-axialwith vessel 246 in which filter 240 is expanded. Vessel 246 and shaft244 have common axis 242. FIG. 19C illustrates longitudinal axis 254 ofshaft 256 not co-axial with axis 252 of lumen 258 in which filter 250 isexpanded.

FIGS. 20A and 20B illustrate an exemplary embodiment including proximalfilter 260 coupled to proximal shaft 262. Filter 260 includes filtermaterial 264, including slack material region 268 adapted to allow thefilter to collapse easier. Filter 260 is also shown with at least onestrut 270 secured to shaft 262, and expansion support 266. As shown inthe highlighted view in FIG. 20B, filter 260 includes seal 274,radiopaque coil 276 (e.g., platinum), support wire 278 (e.g., Nitinolwire), and filter material 264. Any of the features in this embodimentcan be included in any of the filter systems described herein.

FIG. 21 illustrates an exemplary embodiment of a proximal filter.Proximal filter 280 is coupled to proximal shaft 282. Proximal filter280 includes struts 286 extending from proximal shaft 282 to strutrestraint 288, which is adapted to slide axially over distal shaft 284.Proximal filter 280 also includes filter material 290, with porestherein, that extends from proximal shaft 282 to a location axiallybetween proximal shaft 282 and strut restraint 288. Debris can passthrough struts 286 and become trapped within filter material 290. Whenproximal filter 280 is collapsed within a proximal sheath (not shown),struts 286 elongate and move radially inward (towards distal shaft 284).Strut restraint 288 is adapted to move distally over distal shaft 284 toallow the struts to move radially inward and extend a greater lengthalong distal shaft 284.

FIGS. 22A and 22B illustrate an exemplary embodiment of a proximalfilter that can be incorporated into any filter system described herein.The system includes proximal filter 300 and proximal sheath 302, shownin a retracted position in FIG. 22A. Proximal filter 300 includes valveelements 304 in an open configuration in FIG. 22A. When valve elements304 are in the open configuration, foreign particles 306 can passthrough opening 308 and through the valve and become trapped in proximalfilter 300, as is shown in FIG. 22A. To collapse proximal filter 300,proximal sheath 302 is advanced distally relative to proximal filter300. As the filter begins to collapse, the valve elements are broughtcloser towards one another and into a closed configuration, as shown inFIG. 22B. The closed valve prevents extrusion of debris during therecapture process.

The distal filters shown are merely exemplary and other filters may beincorporated into any of the systems herein. FIG. 23A illustrates aportion of an exemplary filter system. The system includes guidingmember 340 (distal sheath not shown), strut 342, expansion support 344,and filter element 346. Strut 342 is secured directly to guiding member340 and strut 342 is secured either directly or indirectly to expansionsupport 344. Filter material 346 is secured to expansion support 344.Distal end 348 of filter material 346 is secured to guiding member 340.

FIG. 23B illustrates a portion of an exemplary filter system. The systemincludes guiding element 350, strut support 352 secured to guidingelement 350, strut 354, expansion support 356, and filter material 358.Strut support 352 can be secured to guiding element 350 in any suitablemanner (e.g., bonding), and strut 354 can be secured to strut support352 in any suitable manner.

FIG. 23C illustrates a portion of an exemplary filter system. The systemincludes guiding element 360, strut support 362 secured to guidingelement 360, strut 364, expansion support 366, and filter material 368.Expansion support 366 is adapted to be disposed at an angle relative tothe longitudinal axis of guiding member 360 when the distal filter is inthe expanded configuration. Expansion support 366 includes trailingportion 362 and leading portion 361. Strut 364 is secured to expansionsupport 366 at or near leading portion 361. FIG. 23D illustrates anexemplary embodiment that includes guiding member 370, strut support372, strut 374, expansion support 376, and filter material 378.Expansion support 376 includes leading portion 373, and trailing portion371, wherein strut 374 is secured to expansion element 376 at or neartrailing portion 371. Expansion support 376 is disposed at an anglerelative to the longitudinal axis of guiding member 370 when the distalfilter is in the expanded configuration.

FIG. 23E illustrates an exemplary embodiment of a distal filter in anexpanded configuration. Guiding member 380 is secured to strut support382, and the filter includes a plurality of struts 384 secured to strutsupport 382 and to expansion support 386. Filter material 388 is securedto expansion support 386. While four struts are shown, the distal filtermay include any number of struts.

FIG. 23F illustrates an exemplary embodiment of a distal filter in anexpanded configuration. Proximal stop 392 and distal stop 394 aresecured to guiding member 390. The distal filter includes tubular member396 that is axially slidable over guiding member 390, but is restrictedin both directions by stops 392 and 394. Strut 398 is secured toslidable member 396 and to expansion support 393. Filter material 395 issecured to slidable member 396. If member 396 slides axially relative toguiding member 390, filter material 395 moves as well. Member 396 isalso adapted to rotate in the direction “R” relative to guiding member390. The distal filter is therefore adapted to independently moveaxially and rotationally, limited in axial translation by stops 392 and394. The distal filter is therefore adapted such that bumping of theguiding member or the distal sheath will not disrupt the distal filteropposition, positioning, or effectiveness.

As shown in FIGS. 23A-23B, in some embodiments, the strut 342, 354 has astraight configuration. A straight configuration may allow for a shorterattachment between the filter and the guiding member. In otherembodiments, as shown in FIGS. 23C-23D, the strut 364, 374, takes acurved configuration. In still other embodiments, the strut has two ormore curves. For example, the strut may take a sinusoidal configurationand transition from a first curve to the opposite curve to aid intransition to the filter frame. In some embodiments, the first curve mayhave a larger radius than the opposite curve. In still otherembodiments, the first curve may have a smaller radius than the oppositecurve.

FIGS. 24A-24C illustrate exemplary embodiments in which the systemincludes at least one distal filter positioning, or stabilizing, anchor.The positioning anchor(s) can help position the distal anchor in aproper position and/or orientation within a bodily lumen. In FIG. 24Athe system includes distal filter 400 and positioning anchor 402. Anchor402 includes expandable stent 404 and expandable supports 406. Supports406 and filter 400 are both secured to the guiding member. Anchor 402can be any suitable type of expandable anchor, such as, for examplewithout limitation, stent 404. Anchor 402 can be self-expandable,expandable by an expansion mechanism, or a combination thereof. In FIG.24A, stent 404 can alternatively be expanded by an expansion balloon.Anchor 402 is disposed proximal to filter 400. FIG. 24B illustrates anembodiment in which the system includes first and second anchors 412 and414, one of which is proximal to filter 410, while the other is distalto filter 410. FIG. 24C illustrates an embodiment in which anchor 422 isdistal relative to filter 420.

In some embodiments the distal filter is coupled, or secured, to aguiding member that has already been advanced to a location within thesubject. The distal filter is therefore coupled to the guiding memberafter the distal filter has been advanced into the subject, rather thanwhen the filter is outside of the subject. Once coupled together insidethe subject, the guiding member can be moved (e.g., axially translated)to control the movement of the distal filter. In some embodiments theguiding member has a first locking element adapted to engage a secondlocking element on the distal filter assembly such that movement of theguiding member moves the distal filter in a first direction. In someembodiments the distal filter assembly has a third locking element thatis adapted to engage the first locking element of the guiding membersuch that movement of the guiding member in a second direction causesthe distal filter to move with the guiding member in the seconddirection. The guiding member can therefore be locked to the distalfilter such that movement of the guiding member in a first and a seconddirection will move the distal filter in the first and seconddirections.

By way of example, FIGS. 25A-25D illustrate an exemplary embodiment ofcoupling the distal filter to a docking wire inside of the subject,wherein the docking wire is subsequently used to control the movement ofthe distal filter relative to the distal sheath. In FIG. 25A, guidecatheter 440 has been advanced through the subject until the distal endis in or near the brachiocephalic trunk 441. A docking wire, comprisinga wire 445, locking element 442, and tip 444, has been advanced throughguide catheter 440, either alone, or optionally after guiding wire 446has been advanced into position. Guiding wire 446 can be used to assistin advancing the docking wire through guide catheter 440. As shown, thedocking wire has been advanced from the distal end of guide catheter440. After the docking wire is advanced to the desired position, guidecatheter 440, and if guiding wire 446 is used, are removed from thesubject, leaving the docking wire in place within the subject, as shownin FIG. 25B. Next, as shown in FIG. 25C, the filter system, includingproximal sheath 448 with a proximal filter in a collapsed configurationtherein (not shown), distal sheath 450, with a distal filter assembly(not shown) partially disposed therein, is advanced over wire 445 untila locking portion of the distal filter (not shown but described indetail below) engages locking element 442. The distal filter assemblywill thereafter move (e.g., axially) with the docking wire. Proximalsheath 448 is retracted to allow proximal filter 454 to expand (see FIG.25D). Distal sheath 450 is then actuated (e.g., bent, rotated, and/ortranslated axially) until it is in the position shown in FIG. 25D. Astraightened configuration of the distal sheath is shown in phantom inFIG. 25D, prior to bending, proximal movement, and/or bending. Thedocking wire is then advanced distally relative to distal sheath 450,which advances distal filter 456 from distal sheath 450, allowing distalfilter 456 to expand inside the left common carotid artery, as shown inFIG. 25D.

FIGS. 26A-26D illustrate an exemplary method of preparing an exemplarydistal filter assembly for use. FIG. 26A illustrates a portion of thefilter system including proximal sheath 470, proximal filter 472 is anexpanded configuration, distal shaft 474, and articulatable distalsheath 476. Distal filter assembly 478 includes an elongate member 480defining a lumen therein. Elongate member 480 is coupled to distal tip490. Strut 484 is secured both to strut support 482, which is secured toelongate member 480, and expansion support 486. Filter element 488 haspores therein and is secured to expansion support 486 and elongatemember 480. To load distal filter assembly 478 into distal sheath 476,loading mandrel 492 is advanced through distal tip 490 and elongatemember 480 and pushed against distal tip 490 until distal filterassembly 478 is disposed within distal sheath 476, as shown in FIG. 26C.Distal tip 490 of the filter assembly remains substantially distal todistal sheath 476, and is secured to the distal end of distal sheath476. Distal tip 490 and distal sheath 476 can be secured together by africtional fit or other type of suitable fit that disengages asdescribed below. Loading mandrel 492 is then removed from the distalfilter and distal sheath assembly, as shown in FIG. 26D.

FIG. 26E illustrates docking wire 500 including wire 502, lock element504, and distal tip 506. Docking wire 500 is first advanced to a desiredposition within the subject, such as is shown in FIG. 25B. The assemblyfrom FIG. 26D is then advanced over docking wire, wherein distal tip 490is first advanced over the docking wire. As shown in the highlightedview in FIG. 26F, distal tip 490 of the distal filter assembly includesfirst locking elements 510, shown as barbs. As the filter/sheathassembly continues to be distally advanced relative to the docking wire,the docking wire locking element 504 pushes locks 510 outward in thedirection of the arrows in FIG. 26F. After lock 504 passes locks 510,locks 510 spring back inwards in the direction of the arrows shown inFIG. 26G. In this position, when docking wire 500 is advanced distally(shown in FIG. 26F), lock element 504 engages with lock elements 510,and the lock element 504 pushes the distal filter assembly in the distaldirection. In this manner the distal filter can be distally advancedrelative to the distal sheath to expand the distal filter. Additionally,when the docking wire is retracted proximally, locking element 504engages the distal end 512 of elongate member 480 and pulls the distalfilter in the proximal direction. This is done to retrieve and/orrecollapse the distal filter back into the distal sheath after it hasbeen expanded.

FIGS. 27A and 27B illustrate an exemplary embodiment in which guidingmember 540, secured to distal filter 530 before introduction into thesubject is loaded into articulatable distal sheath 524. The system alsoincludes proximal filter 520, proximal sheath 522, and distal shaft 526.FIG. 27B shows the system in a delivery configuration in which bothfilters are collapsed.

FIGS. 28A-28E illustrate an exemplary distal filter assembly incollapsed and expanded configurations. In FIG. 28A, distal filterassembly 550 includes a distal frame, which includes strut 554 andexpansion support 555. The distal frame is secured to floating anchor558, which is adapted to slide axially on elongate member 564 betweendistal stop 560 and proximal stop 562, as illustrated by the arrows inFIG. 28A. The distal filter assembly also includes membrane 552, whichhas pores therein and is secured at its distal end to elongate member564. The distal filter assembly is secured to a guiding member, whichincludes wire 566 and soft distal tip 568. The guiding member can be,for example, similar to the docking wire shown in FIGS. 26A-26E above,and can be secured to the distal filter assembly as described in thatembodiment.

The floating anchor 558 allows filter membrane 552 to return to aneutral, or at-rest, state when expanded, as shown in FIG. 28A. In itsneutral state, there is substantially no tension applied to the filtermembrane. The neutral deployed state allows for optimal filter frameorientation and vessel apposition. In the neutral state shown in FIG.28A, floating anchor 558 is roughly mid-way between distal stop 560 andproximal stop 562, but this is not intended to be a limiting positionwhen the distal filter is in a neutral state.

FIG. 28B illustrates the distal filter being sheathed into distal sheath572. During the sheathing process, the distal filter is collapsed froman expanded configuration (see FIG. 28A) towards a collapsedconfiguration (see FIG. 28C). In FIG. 28B, distal sheath 572 is movingdistally relative to the distal filter. The distal end of the distalsheath 572 engages with strut 554 as it is advanced distally, causingthe distal end of strut 554 to moves towards elongate member 564. Strut554 can be thought of as collapsing towards elongate member 564 from theconfiguration shown in FIG. 28A. The force applied from distal sheath572 to strut 554 collapses the strut, and at the same time causesfloating anchor 558 to move distally on tubular member 564 towardsdistal stop 560. In FIG. 28B, floating anchor 558 has been moveddistally and is engaging distal stop 560, preventing any further distalmovement of floating anchor 558. As strut 554 is collapsed by distalsheath 572, strut 554 will force the attachment point between strut 554and expansion support 555 towards tubular member 564, beginning thecollapse of expansion support 555. Distal sheath 572 continues to beadvanced distally relative to the distal filter (or the distal filter ispulled proximally relative to the distal sheath, or a combination ofboth) until the distal filter is collapsed within distal sheath 572, asis shown in FIG. 28C. Filter membrane 552 is bunched to some degree whenthe filter is in the configuration shown in FIG. 28C. To deploy thedistal filter from the sheath, guiding member 566 is advanced distallyrelative to the distal sheath (or the distal sheath is moved proximallyrelative to the filter). The distal portions of filter membrane 552 andexpansion support 555 are deployed first, as is shown in FIG. 28D.Tension in the filter membrane prevents wadding and binding during thedeployment. When strut 554 is deployed from the distal sheath, expansionsupport 555 and strut 554 are able to self-expand to an at-restconfiguration, as shown in FIG. 28E. Floating anchor 558 is pulled inthe distal direction from the position shown in FIG. 28D to the positionshown in FIG. 28E due to the expansion of strut 554.

FIGS. 29A-29E illustrate a portion of an exemplary filter system with alower delivery and insertion profile. In FIG. 29A, the system includesproximal sheath 604 with a larger outer diameter than distal sheath 602.In some embodiments proximal sheath 604 has a 6 F outer diameter, whiledistal sheath 602 has a 5 F outer diameter. A guiding member includingdistal tip 606 is disposed within the distal sheath and the proximalsheath. FIG. 29B illustrates tear-away introducer 608, with receivingopening 610 and distal end 612. Introducer is first positioned within asubject with receiving opening 610 remaining outside the patient. Asshown in FIG. 29C, the smaller diameter distal sheath is first advancedthrough the receiving opening of introducer 608 until the distal end ofthe distal sheath is disposed distal relative to the distal end of theintroducer. The introducer is then split apart and removed from thesubject, as shown in FIG. 29D. The filter system can then be advanceddistally through the subject. The introducer can be a 5 F introducer,which reduces the insertion and delivery profile of the system.

The embodiments in FIGS. 25A-25B above illustrated some exemplarysystems and methods for routing filter systems to a desired locationwithin a subject, and additional exemplary embodiments will now bedescribed. FIGS. 30A and 30B illustrate an exemplary embodiment similarto that which is shown in FIGS. 27A and 27B. The filter system showsdistal filter 650 and proximal filter 644 in expanded configurations.Proximal sheath 642 has been retracted to allow proximal filter 644 toexpand. Distal filter, which is secured to guiding member 648, are bothadvanced distally relative to distal articulating sheath 640. The filtersystem does not have a dedicated guidewire that is part of the system,but distal sheath 640 is adapted to be rotated and steered to guide thesystem to a target location within the subject.

FIGS. 31A-31C illustrate an exemplary over-the-wire routing system thatincludes a separate distal port for a dedicated guidewire. A portion ofthe system is shown in FIG. 31B, including distal articulating sheath662 and proximal sheath 660 (the filters are collapsed therein). FIG.31B is a highlighted view of a distal region of FIG. 31A, showingguidewire entry port 666 near the distal end 664 of distal sheath 662.FIG. 31C is a sectional view through plane A of distal sheath 662,showing guidewire lumen 672, spine element 678, distal filter lumen 674,and steering element 676 (shown as a pull wire). Guidewire lumen 672 anddistal filter lumen 674 are bi-axial along a portion of distal sheath,but in region 670 guidewire lumen 672 transitions from within the wallof distal sheath 662 to being co-axial with proximal sheath 660.

To deliver the system partially shown in FIGS. 31A-31C, a guidewire isfirst delivered to a target location within the subject. The guidewirecan be any type of guidewire. With the guidewire in position, theproximal end of the guidewire is loaded into guidewire entry port 666.The filter system is then tracked over the guidewire to a desiredposition within the subject. Once the system is in place, the guidewireis withdrawn from the subject, or it can be left in place. The proximaland distal filters can then be deployed as described in any of theembodiments herein.

FIGS. 32A-32E illustrate an exemplary routing system which includes arapid-exchange guidewire delivery. The system includes distalarticulating sheath 680 with guidewire entry port 684 and guidewire exitport 686. The system also includes proximal sheath 682, a distal filtersecured to a guiding member (collapsed within distal sheath 680), and aproximal filter (collapsed within proximal sheath 682). After guidewire688 is advanced into position within the patient, the proximal end ofguidewire 688 is advanced into guidewire entry port 684. Distal sheath(along with the proximal sheath) is tracked over guidewire 688 untilguidewire 688 exits distal sheath 680 at guidewire exit port 686.Including a guidewire exit port near the entry port allows for only aportion of the guidewire to be within the sheath(s), eliminating theneed to have a long segment of guidewire extending proximally from thesubject's entry point. As soon as the guidewire exits the exit port, theproximal end of the guidewire and the proximal sheath can both behandled.

FIG. 32B shows guidewire 688 extending through the guidewire lumen inthe distal sheath and extending proximally from exit port 686. Guidewire688 extends adjacent proximal sheath 682 proximal to exit port 686. InFIG. 32B, portion 690 of proximal sheath 682 has a diameter larger thanportion 692 to accommodate the proximal filter therein. Portion 692 hasa smaller diameter for easier passage of the proximal sheath andguidewire. FIG. 32C shows a sectional view through plane 32C-32C of FIG.32B, with guidewire 688 exterior and adjacent to proximal sheath 682.Proximal filter 694 is in a collapsed configuration within proximalsheath 682, and guiding member 696 is secured to a distal filter, bothof which are disposed within distal shaft 698.

FIG. 32D shows relative cross-sections of exemplary introducer 700, anddistal sheath 680 through plane 32D-32D. Distal sheath 680 includesguidewire lumen 702 and distal filter lumen 704. In some embodiments,introducer 700 is 6 F, with an inner diameter of about 0.082 inches. Incomparison, the distal sheath can have a guidewire lumen of about 0.014inches and distal filter lumen diameter of about 0.077 inches.

FIG. 32E shows a sectional view through plane 32E-32E, and alsoillustrates the insertion through introducer 700. Due to the smallerdiameter of portion 692 of proximal sheath 682, guidewire 688 andproximal sheath 682 more easily fit through introducer 700 than thedistal sheath and portion of the proximal sheath distal to portion 692.The size of the introducer may vary depending on the diameter of thefilter system. The introducer may range in size from 4 F to 15 F. Incertain embodiments, the size of the introducer is between 4 F and 8 F.Guidewire 688 may vary in diameter between 0.005 and 0.02 inches orbetween 0.01 and 0.015 inches. In some situations, it may be desirableto have a guidewire smaller than 0.005 inches or larger than 0.02 inchesin diameter. The smaller diameter proximal portion 692 of proximalsheath 682 allows for optimal sheath and guidewire movement with theintroducer sheath. In certain aspects, it may be desirable for thecross-section of proximal filter deployment member 697 to take anon-circular shape to reduce the profile of proximal sheath 682. Guidingmember 696 and distal sheath pull wire 676 are both disposed throughdistal shaft 698.

In certain embodiments, the guiding member is a core wire. Use of a corewire may be desirable to decrease the diameter of the filter system. Acore wire is also flexible and able to access tortuous anatomies. Thematerial and diameter of the guiding member may vary depending on thedesired level of column strength or flexibility. In certain embodiments,the core wire may be tapered such that a distal section of the core wirehas a smaller diameter than a proximal section of the core wire toincrease flexibility at the distal section.

In certain clinical scenarios, it may be desirable for the guidingmember to take the form of a tubular core member having a guidewirelumen running therethrough. In several embodiments, the tubular coremember is a catheter shaft. The presence of the guidewire lumen allowsthe user to deliver the filter system to the correct position byadvancing the filter system over the guidewire. A tubular core memberallows the user to select an appropriate guidewire for the procedurerather than restricting the user to the wire core shaft. A guidingmember having a guidewire lumen can potentially reduce the deliveryprofile of the filter system by not requiring separate lumens for theguiding member and the guidewire.

FIG. 33A illustrates filter system 700 having tubular core member 720extending along an elongate axis of filter system 700 and slidablydisposed through distal shaft 716. The distal end of tubular core member720 is positioned in a distal, atraumatic tip 740 of filter system 700,while the proximal end of tubular core member 720 is positioned in thecontrol handle. The proximal end of tubular core member 720 is connectedto an actuation mechanism capable of advancing tubular core member 720distally or retracting tubular core member 720 proximally with respectto distal shaft 716. Distal filter assembly 726 may be mounted on adistal section of tubular core member 720. Proximal filter 704 anddistal filter 726 are illustrated as formed from a plurality of strutssuch as a woven wire or laser cut basket, however any of the polymericmembrane filters disclosed elsewhere herein may be used in filter system700.

In certain embodiments, tubular core member 720 defines a guidewirelumen 745. Tubular core member 720 may have a distal guidewire entryport at the distal end of tubular core member 720 and a proximalguidewire exit port at the proximal end of tubular core member 720. Inother embodiments, the proximal guidewire port may be positioned at anyposition along the length of the tubular core member.

The length of tubular core member 720 may range from about 50 cm toabout 300 cm. In some embodiments, the length may be less than 50 cm;while in other embodiments, the length may be greater than 300 cm. Inseveral embodiments, the length of tubular core member 720 is betweenabout 50 and about 150 cm, between about 75 and about 125 cm, or betweenabout 100 cm and about 150 cm. The inner diameter of tubular core member720 may range from about 0.01 to about 0.075 cm. In other embodiments,the inner diameter of tubular core member 720 is less than 0.01 cm;while in still other embodiments, the inner diameter is greater than0.075 cm. The outer diameter of tubular core member 720 may range fromabout 0.025 to about 0.1 cm. In certain embodiments, the outer diameterof tubular core member 720 is less than 0.025 cm; while in otherembodiments, the inner diameter is greater than 0.1 cm.

In certain clinical scenarios, it may be desirable to increase thecolumn strength of tubular core member 720, thus improving support andpushability to aid advancement of distal filter assembly 726 out ofdistal sheath 718. In certain scenarios, tubular core member 720 may beconstructed from a material stiffer than the material from which distalshaft 716 is constructed. A stiffer tubular core member 720 can helpimprove the column strength of filter system 700. The tubular coremember 720 may be constructed from metallic materials such as stainlesssteel, Nitinol, cobalt chromium (MP35N), or other alloys used in medicaldevices. Alternatively, tubular core member 720 may be constructed froma polymer construction such as nylon, polyester, polypropylene,polyimide, or other polymers exhibiting similar properties. In someembodiments, tubular core member 720 may be constructed from acombination of metallic materials and polymeric materials. In someembodiments, the inner diameter of tubular core member 720 is eithercoated with or constructed of a lubricious polymer (e.g. HDPE, PTFE,FEP, etc.). In still other embodiments, tubular core member may includereinforcements. For example, a ribbon or other stiffening member mayextend along a section of tubular core member 720. Alternatively,tubular core member 720 may have a multi-lumen profile, a first lumenfor a guidewire and a second lumen for a stiffening mandrel. Tubularcore member 720 may also transition from a multi-lumen profile to asingle lumen profile to increase flexibility along the single lumensection of the tubular core member. In still other embodiments, tubularcore member 720 may include one or more longitudinal strands dispersedwithin the tubular core member shaft to improve tensile strength. Insome embodiments, tubular core member 720 may have a braided or coiledshaft to increase column strength. In certain embodiments, the braidconsists of both metallic and polymer materials. In other embodiments,the braid consists of only metal; while in still other embodiments, thebraid consists of only polymer materials.

In other clinical scenarios, it may be desirable to provide moreflexibility in certain sections or along the entire length of tubularcore member 720. When filter system 700 is deployed in a curved lumen, arigid tubular core member 720 or other guiding member may pull theleading portion 732 of distal filter 736 away from the vessel wall ifthe distal region of tubular core member 720 or other guiding memberlacks sufficient flexibility to deflect relative to filter system 700 ina tortuous anatomy.

In certain embodiments, tubular core member 720 may be constructed froma more flexible material. In other embodiments, a first portion oftubular core member 720 may be constructed from a flexible material,while a second portion of tubular core member 720 is constructed from astiffer material. Alternatively, removal of portions of tubular coremember 720 may provide greater flexibility along certain sections oftubular core member 720. For example, a series of slots, cuts, or aspiral pattern may be cut into a section of tubular core member 720 toprovide a flex zone having a greater flexibility than proximal anddistal adjacent portions of tubular core member 720. The pattern of cutsmay vary along the tubular core member shaft to vary flexibility alongtubular core member 720. The flexible portion may alternatively comprisea coil, helix, or interrupted helix. In other embodiments, a firstportion of the tubular core member may also have a thinner wall than asecond portion of the tubular core member. In still other embodiments,tubular core member 720 may be tapered to increase stiffness along afirst section of the tubular core member and increase flexibility alonga second section of the tubular core member.

In certain embodiments, a distal section of tubular core member 720 maybe more flexible than a proximal section of the tubular core member 720using any of the methods discussed above. The length of the flexibledistal section may measure from about 5 cm to about 50 cm, from about 10to about 40 cm, or from about 15 to about 25 cm. In other embodiments,the flexible distal section may be less than 5 cm or greater than 50 cm.

Several embodiments may include a flexible coupler 722 to allow distalfilter assembly 726 to deflect relative to the rest of filter system700. In several embodiments, tubular core member 720 includes a flexiblecoupler 722 positioned proximal to distal filter assembly 726. Inseveral embodiments, flexible coupler 722 defines a lumen through whicha guidewire may pass. In some embodiments, flexible coupler 722 isspliced into a gap along tubular core member 720. In some embodiments,tubular core member 720 may comprise a distal tubular core member and aproximal tubular core member. The distal end of the proximal tubularcore member may be joined to the proximal end of flexible coupler 722,while the proximal end of the distal tubular core member is joined tothe distal end of flexible coupler 722. In still other embodiments,tubular core member 720 and flexible coupler 722 are integrally formedsuch as by providing core member 720 with a plurality of transverseslots as is described elsewhere herein.

In some clinical scenarios, it may be desirable for flexible coupler 722to be more flexible than tubular core member 720, while stilldemonstrating properties strong enough to resist deformation undertensile loads. Flexible coupler 722 may be constructed from materials,such as polymers, multiple polymers, Nitinol, stainless steel, etc. Incertain embodiments, flexible coupler 722 may be created by piercing,slotting, grooving, scoring, cutting, laser cutting or otherwiseremoving material from a tubular body to increase flexibility.Alternatively, a flexible coupler 722 may be integrally formed withtubular core member 720 using any of the above mentioned patterns. Inanother embodiment, flexible coupler 722 is created by thinning aportion of tubular core member 720 to create a more flexible region.Flexible coupler 722 may also be deformed into a serrated or bellowsshape without removing any material from the tubular body. Any of theother methods discussed above to increase the flexibility of tubularcore member 720 may also be applied.

In some embodiments, a flexible section 738 of tubular core member 722may be configured to be more flexible than a proximal section of tubularcore member 722. In some aspects, flexible section 738 is positioneddistal to flexible coupler 722. The length of flexible section 738 maymeasure from about 5 mm to about 50 mm, from about 10 to about 30 mm, orfrom about 20 to about 40 mm. In other embodiments, the flexible distalsection may be less than 5 mm or greater than 50 mm.

FIGS. 33B-D illustrate cross sections at various positions along thedual filter system depicted in FIG. 33A. FIG. 33B illustrates a crosssection of filter system 700, proximal to proximal filter assembly 704.Guidewire 721 is disposed through a lumen defined by tubular core member720, and tubular core member 720 is disposed through a lumen defined bydistal shaft 716. In certain embodiments, at least a portion of distalsheath 718 may be articulated via pull wire 737. FIG. 33B shows that atleast a portion of pull wire 737 may be disposed through distal shaft716, but external to tubular core member 720. In some embodiments, atleast a portion of pull wire 737 may pass through a lumen embedded in atleast a portion of the distal shaft wall or distal sheath wall. In FIG.33B, a portion of distal shaft 716 may be disposed through a lumendefined by proximal shaft 701. Proximal filter frame 714 may extendthrough a lumen embedded in at least a portion of the proximal filtershaft wall 701. Proximal filter shaft 701 is disposed through a lumendefined by proximal sheath 702.

FIG. 33C depicts a cross section distal to the cross section depicted inFIG. 33B through distal sheath 718. Distal sheath is illustrated in asimplified form, but typically will include all of the deflectionmechanisms of FIGS. 9A-9E, discussed above. FIG. 33C shows guidewire 721disposed through a lumen defined by tubular core member 720. At least aportion of tubular core member 720 is disposed through a lumen definedby distal sheath 718. As depicted in 33C, at least a portion of distalsheath 718 may be provided with a reinforcement such as an embedded coilor braid 719 to improve torquing capabilities. In some embodiments, theentire length of distal sheath 718 may comprise a reinforcing elementsuch as a braid. Pull wire 737 may extend through a lumen extendingthrough at least a portion of the distal sheath 718, and distal sheathspinal element 741 may extend through at least a portion of distalsheath 718. In some embodiments, the outer diameter of distal sheath 718is substantially similar to the outer diameter of proximal sheath 702.In other embodiments, distal sheath 718 extends through a lumen definedby proximal sheath 702.

FIG. 33D depicts a cross section distal to the cross-section depicted inFIG. 33C. FIG. 33D shows guidewire 721 disposed through a lumen definedby tubular core member 720. Tubular core member 720 is coaxial withflexible coupler 722. In certain embodiments, the diameter of flexiblecoupler 722 may be larger than the diameter of tubular core member 720.In other embodiments, flexible coupler 722 may have the same diameter astubular core member 720. In still other embodiments, the diameter offlexible coupler 722 may be smaller than the diameter of tubular coremember 720. In certain embodiments, the flexible coupler may not be aseparate component.

As shown in FIGS. 34A-C, a tubular core member 720 coupled with aflexible coupler 722 has the advantage of providing improved columnstrength along a substantial length of the filter system 700, butproviding the flexibility necessary for distal filter assembly 726 toposition itself independent of the position of distal shaft 716.Flexible coupler 722 allows distal filter frame element 728 to create abetter seal against the vessel wall to help prevent embolic debris fromflowing between distal filter 736 and the vessel wall.

A filter system having a flexible coupler 722 is deployed similarly tothe method described in FIGS. 2A-2D. In one embodiment, as distal sheath718 is advanced into the left common carotid artery, tubular core member720 is advanced distally relative to distal sheath 718. FIG. 34Billustrates filter system 700 after tubular core member 720 is advancedinto the left common carotid artery. Distal filter 736 expands andflexible coupler 722 deflects relative to filter system 700 such thatdistal filter frame element 728 is circumferentially apposed to thevessel wall. Strut 724 may be proximally retracted as desired to tiltthe frame element 728 to improve the fit of the distal filter 736 withinthe vessel.

In certain embodiments, the stiffness of tubular core member 720 may befurther reduced during use by the operator by withdrawing the guidewireuntil the distal end of the guidewire is proximal to flexible coupler722 such that the guidewire is no longer disposed within flexiblecoupler 722, thus reducing stiffness.

FIGS. 35A-B illustrate a tubular body 750 suitable for use as a flexiblecoupler 722. A tubular body 750 having a proximal end 754 and a distalend 756 may be formed by wrapping a ribbon or wire around a mandrel orby laser cutting a tube with a spiral pattern to form a coil. The widthof spaced regions 752 a,b between each adjacent coil loop 751 may bedifferent in an unstressed orientation depending on the desiredproperties. In some embodiments, it may be desirable to provide greaterflexibility, in which case, spaced region 752 b should be wider to allowfor a greater range of movement. In certain clinical scenarios, it maybe desirable to provide smaller spaced regions 752 a between each coilportion 751 to help prevent a first edge 753 a and a second edge 753 bof each coil portion 751 from dislodging plaque from the vessel wall ordamaging the vessel wall. In an alternate embodiment, a flexible coupler722 having wider spaced regions 752 a between each coil portion 751 maybe covered by a thin sheath such as shrink wrap tubing to provideflexibility and protect the vessel wall from flexible coupler 722.

In FIG. 35C, a tubular body 760 having a proximal end 764 and a distalend 766 is laser cut with a plurality of slots 762, each slot 762 havinga first end 768 a and a second end 768 b. In some embodiments, two ormore slots 762 form a circumferential ring 771 around flexible coupler722. In several embodiments, a plurality of circumferential rings 771 islaser cut into a tubular body 760. The plurality of circumferentialrings 771 may be staggered such that a first slot of a firstcircumferential ring is misaligned from a first slot of a secondcircumferential ring. The plurality of slots 762 are configured suchthat flexible coupler 722 flexes angularly while retaining good torqueresistance and tensile displacement resistance.

FIG. 35D depicts a flexible coupler 722 constructed from a tubular body770 having a proximal end 774 and a distal end 776. Tubular body 770 islaser cut with a spiral pattern, the spiral pattern having a pluralityof interlocking ring portions, wherein a first interlocking ring portion778 a interlocks with a complementary second interlocking ring portion778 b. Flexible coupler 722 has an interlocking pattern designed toresist axial deformation (stretching) when placed in tension. FIG. 35Eillustrates flexible coupler 722 also having interlocking ring portions778. In this embodiment, an axial element 784 is positioned across aninterlocking feature 782 to improve the axial stiffness of flexiblecoupler 722 when subject to tensile loading.

Although the above mentioned embodiments were discussed in connectionwith a tubular core member, the same properties may be applied to anyother guiding member. The guiding member may incorporate any of theabove mentioned properties alone, or in combination, to manipulateflexibility and column strength along the guiding member shaft. Theembodiments may also be used in connection with the proximal filter orany other catheter-based system.

In certain clinical scenarios, it may be desirable for the filteropening to circumferentially appose the vessel wall. This helps preventdebris from flowing past the filter. In a straight lumen, a filter canachieve good apposition with the vessel wall, thus preventing plaque orblood clots from flowing past the filter when it is deployed in avessel. In contrast, when a filter is deployed in a curved lumen, thefilter frame element can settle into a number of different rotationalorientations in the lumen. In some clinical scenarios, when the filteris deployed in a curved lumen, it is possible for the filter frameelement to pull away from the vessel wall particularly on the innerradius thus leading to poor apposition and blood leakage past thefilter.

In current settings, practitioners may seek to overcome this poorpositioning by using contrast injections and fluoroscopic imaging in oneor more views. The filter is then either re-sheathed and redeployed orrotated or repositioned without re-sheathing, a process that candislodge plaque from the vessel wall or otherwise damage the vessel.Neither of these solutions is satisfactory due to the extended proceduretime and the increased possibility of vessel damage due to increaseddevice manipulation.

In certain scenarios, it may be advantageous to add a tethering memberto a filter assembly. FIGS. 36A-E illustrate tethering member 842attached to proximal filter assembly 804. Tethering member 842 isconfigured to draw proximal filter frame element 814 closer to thevessel wall in order to form a seal with the inner surface of thevessel. Proper apposition of proximal filter assembly 804 relative tothe vessel wall prevents debris from flowing past proximal filterassembly 804. This can be achieved with a flexible tethering member(e.g. monofilament polymer, braided polymer, suture, wire, etc.) or witha rigid or semi-rigid member such as nitinol, thermoplastic, stainlesssteel, etc.

Tethering member 842 has a first end 844 and a second end 846. In FIG.36A, the first end 844 of tethering member 842 is affixed to proximalsheath 802, while the second end 846 of tethering member 842 is affixedto proximal filter assembly 804. In some embodiments, tethering member842 is affixed to filter frame element 814; while in other embodiments,tethering member 842 is affixed to proximal filter 806. FIGS. 36B-Cillustrate how tethering member 842 laterally deflects the frame 814 andpulls filter frame element 814 toward the vessel wall when the operatorretracts proximal sheath 802. Proximally retracting tethering member 842allows the operator to control the deflection and angle of proximalfilter frame element 814. In other embodiments, tethering member 842 canbe actuated passively rather than actively (i.e. by the operator) byforming tethering member 842 from an elastic material or spring in orderto elastically pull the edge of proximal filter frame element 814 towardthe vessel wall.

In still other embodiments, the second end 846 of tethering member 842may be attached to a feature disposed along proximal filter 806. Forexample, in FIG. 36E, the second end 846 of tethering member 842 isconnected to a rib 848 formed on proximal filter 806. In still otherembodiments, the first end 844 of tethering member 842 may be attachedto an elongate member such as a pull wire slidably disposed along thelength of the catheter system to a control actuator in the controlhandle. This allows the operator to control the deflection of proximalfilter frame element 814 independently from proximal sheath 802.

In certain embodiments, it may be preferable to attach a distal end oftethering member 842 to a single location on proximal filter assembly804. Alternatively, as shown in FIG. 36D, it may be preferable to attachthe distal end of tethering member 842 to two or more positions onproximal filter assembly 804.

In order to facilitate sheathing and to minimize tangling when proximalfilter assembly 804 is collapsed into proximal sheath 802, tetheringmember 842 may be twisted to form a coil 849, as shown in FIG. 37A.Twisted portion 849 retracts and stays out of the way when proximalfilter assembly 804 is sheathed, and twisted portion 849 will untwistand straighten as the operator deploys proximal filter assembly 804. Thedesign is also helpful for controlling the slack in tethering member 842during sheathing and unsheathing. Tethering member 842 may be formedfrom a heat deformable polymer and applying heat to deform the polymerinto a twisted configuration. Tethering member may alternatively beformed from nitinol or any other material having suitable properties. Inother embodiments, it may be preferable for tethering member 842 to forma coil (FIG. 37B), pre-formed to particular shapes (FIG. 37C), or havetwo or more tethering members (FIG. 37D). One or more tethering membersmay be formed into any other design that may decrease the likelihoodthat tethering member 842 will become tangled with other catheters ordevices.

Although the previously discussed tethering members have been discussedin connection with proximal filter assemblies, a tethering member may beused in connection with a distal filter, other filter devices, or anyintraluminal device that may desirably be laterally displaced, tilted orotherwise manipulated into a desired orientation, such as to improvealignment including improving apposition with a vessel wall.

In some clinical scenarios, it may be desirable to place a single filterin a blood vessel. Any of the above mentioned features of the dualfilter embodiments may be applied to the single filter embodimentsdescribed below, including, but not limited to, filter design, sheatharticulation, or guiding member flexibility or column strength. Inaddition, filter systems described herein can be utilized in connectionwith a variety of intravascular interventions. The embodiments describedbelow will be discussed in connection with a TAVI procedure, but thefilter systems may be used with other intravascular or surgicalinterventions such as balloon valvuloplasty, coronary artery bypassgrafting, surgical valve replacement, etc. and should not be construedas limited to the TAVI procedure.

In certain situations, it may be desirable to position the filter in theaorta, distal to the aortic valve but proximal to the brachiocephalicartery ostium, such that the entire arterial blood supply can befiltered. The aortic filter may also be positioned in the aorta, betweenthe right brachiocephalic artery ostium and the left carotid arteryostium. In other scenarios, the aortic filter may be positioned betweenthe left carotid artery ostium and the left subclavian artery ostium,while in still other clinical situations may make it preferable toposition the aortic filter in the descending aorta, distal to the leftsubclavian artery ostium. In some cases, an aortic filter can bepositioned in the aorta in combination with brachiocephalic and leftcarotid artery filters in order to capture all embolic debris.

An aortic filter can be positioned at various locations along a cathetersystem. In one embodiment, the aortic filter can be positioned on acatheter separate from the TAVI or pigtail catheter and inserted throughthe left or right brachial artery or the right or left femoral artery.Using a separate aortic filter catheter decreases the overall diameterof the TAVI catheter and allows the operator to position the aorticfilter independently from aortic valve. Further, the aortic filter willnot dislodge plaque along the vessel wall when the TAVI catheter isrepositioned or rotated.

In another embodiment, the aortic filter can be positioned on the TAVIcatheter shaft, proximal to the valve prosthesis. To decrease the sizeof the overall catheter system, the diameter of the TAVI catheter systemproximal to the valve prosthesis may be reduced in size. This embodimentdecreases the number of total devices in the operating environment, thusdecreasing the likelihood that devices will get tangled.

In yet another embodiment, the aortic filter may be positioned on theTAVI introducer. This embodiment enables the operator to position theaortic filter independently from the position of the TAVI catheter. Thefilter is also less likely to dislodge plaque along the vessel wall whenthe TAVI catheter is repositioned or rotated. Introducing the aorticfilter on the TAVI introducer also decreases the total number ofcatheters into the operating environment.

In still another embodiment, the aortic filter is positioned on apigtail catheter shaft, proximal to the pigtail. Affixing the aorticfilter to the pigtail catheter does not increase the overall diameter ofthe TAVI system or add any additional catheters into the operatingenvironment.

In one embodiment, the aortic filter is positioned on an extendedpigtail introducer sheath. This embodiment enables the operator toposition the aortic filter separately from the location of the pigtailwithout adding any additional catheters into the operating environment.Positioning the aortic filter on the pigtail introducer sheath also doesnot increase the overall diameter of the TAVI system. Further, theaortic filter will not dislodge plaque along the vessel while when thepigtail and/or TAVI catheter is repositioned or rotated.

Various methods can be used to perform a TAVI procedure in connectionwith an aortic filter. In one method, the aortic filter is positioned asearly as possible in the procedure at any location in the aortapreviously described, and the aortic filter may be deployed using any ofthe above mentioned devices. The TAVI catheter may then be insertedthrough the filter and the TAVI implantation is performed. Afterward,the TAVI catheter and aortic filter are removed.

In an alternative method, a guidewire is positioned through the aortaand the pigtail catheter is inserted into the aorta. A TAVI catheter canthen be advanced to a position just proximal of where the aortic filterwill be deployed. The aortic filter may be deployed at any positiondescribed above. Using any of the previously discussed embodiments, acatheter carrying an aortic filter deploys an aortic filter in theaorta. The aortic filter also forms a seal against both the TAVIcatheter and the vessel wall such that debris cannot flow past thefilter. After the aortic filter is deployed, the TAVI catheter isadvanced to the implant location and the implant procedure is performed.When the procedure is over, the TAVI catheter is withdrawn just proximalto the filter such that the operator can retrieve the aortic filter. Theaortic filter, TAVI, and pigtail catheters are then all withdrawn fromthe operating environment. These steps are not limited to the order inwhich they were disclosed. For example, the TAVI catheter may beadvanced to the implant location before the aortic filter is deployed.

FIG. 38A depicts a TAVI catheter 933 that is deployed across an aorticfilter assembly 904 in the aorta 999. In some scenarios, aortic filterassembly 904 may not fully appose the TAVI catheter shaft, thus leavingroom for debris to flow between the TAVI catheter 933 and the vesselwall. In these scenarios, it may be preferential to configure aorticfilter assembly 904 to appose TAVI catheter 933 and preventsubstantially all debris from flowing past aortic filter assembly 904without significantly degrading filter capture performance. It may alsobe preferential to modify aortic filter assembly 904 in scenarios whereTAVI catheter 933 passes through aortic filter assembly 904.

FIG. 38B illustrates an aortic filter assembly 904 designed to pass overa guidewire 907 or other guiding member. Aortic filter assembly 904 mayhave a channel 909 on the exterior surface of aortic filter assembly904. Channel 909 is constructed such that a TAVI deployment catheter orother catheter may pass through channel 909. The operator may alsorotate aortic filter assembly 904 such that the TAVI catheter properlypasses through channel 909. The control handle may indicate therotational location of channel 909 help the operator correctly orientaortic filter 904. Alternatively, channel 909 may have at least one ortwo radiopaque markers to enable identification of channel 909 usingfluoroscopy.

FIG. 38C depicts aortic filter assembly 904 having a leading edge 911and a trailing edge 913. Aortic filter assembly 904 passes over aguidewire 907 or other guiding member. Leading edge 911 overlapstrailing edge 913 to form an overlapping portion 935. The control handlemay indicate the location of overlapping portion 935 so the operator cantorque aortic filter assembly 904 to position overlapping portion 935over the TAVI or other catheter shaft. Overlapping portion 935 may havea radiopaque marker to allow the operator to monitor aortic filterplacement under fluoroscopy.

FIG. 38D depicts an aortic filter assembly 904 designed to pass over aguidewire 907 or other guiding member. Aortic filter 904 has a firstfilter portion 915 and a second filter portion 917, second filterportion 917 having a first edge 917 a, and a second edge 917 b. Thefirst edge 917 a and the second edge 917 b of second filter portion 917overlap first filter portion 915 to form a joint 914. The control handlemay indicate the location of joint 914 so the operator can torque aorticfilter assembly 904 to position joint 914 against the shaft of the TAVIcatheter. As the operator advances a catheter-based device across aorticfilter 904, second filter portion 917 caves inward such that joint 914forms a seal around the catheter shaft. Aortic filter assembly 904 mayinclude a radiopaque marker to allow the operator to identify joint 914under fluoroscopy.

FIGS. 39 A-C depict an aortic filter device having two or three or fouror more aortic lobes or filters. Each aortic filter lobe 904 a,b,c isjoined together along a first side 919 of each aortic filter lobe 904a,b,c. Aortic filter lobes 904 a,b,c join together about a longitudinalaxis of the aortic filter system. The aortic filter system is configuredsuch that a TAVI catheter 933 or other catheter-based device may passbetween a first aortic filter assembly 904 b and a second aortic filterassembly 904 c. The first and second aortic filters 904 b,c forming aseal around the TAVI catheter 933, thus preventing debris from flowingpast the aortic filter system.

FIG. 40A depicts generally conical aortic filter assembly 904 resemblingan umbrella. Aortic filter 904 may pass over a guidewire 907 or otherguiding member. Aortic filter assembly 904 has a plurality ofself-expanding tines 923, each tine having a proximal end and a distalend. Each tine joins together at a first end 903 of aortic filterassembly 904. In addition, a filter portion 925 is suspended betweentines 923. Filter portion 925 may be fairly inflexible or flexible tostretch over the TAVI catheter 933 or other catheter-based device. Whenan operator advances TAVI catheter 933 past aortic filter assembly 904,TAVI catheter 933 passes between a first tine 923 and a second tine 923such that a filter portion 925 stretches over TAVI catheter 933 to forma seal between filter portion 925 and TAVI catheter 933.

Alternatively, FIG. 40B depicts an aortic filter assembly 904 resemblinga flower. In one embodiment, aortic filter assembly 904 has two or morepetals 943 arranged in a circular array that allow TAVI catheter 933 orother catheter-based device to pass between petals 943. Petals 943 mayoverlap one another to create a seal between adjacent petals 943. Petals943 also create a seal around TAVI catheter 933 as the catheter passesbetween petals 943. The shape of each petal 943 may include an arch tobetter accommodate the circular shape of the aorta. Each petal 943 mayhave a length between two to six centimeters. Although in someembodiments, the length may be less than in two centimeters; while instill other embodiments, the length may be greater than six centimeters.In one embodiment, the individual petals are comprised of a frame 944that is covered with a filter element 945. The frame 944 may beconstructed of a shape memory material such as Nitinol, or othermaterial such as stainless steel, cobalt supper alloy (MP35N forexample) that has suitable material properties. The filter element 945may be constructed of a polyurethane sheet that has been pierced orlaser drilled with holes of a suitable size. Other polymers may also beused to form the filter element, in the form of a perforated sheet orwoven or braided membranes. Thin membranes or woven filament filterelements may alternatively comprise metal or metal alloys, such asnitinol, stainless steel, etc.

Any of the aortic filter assemblies described above may also includeframe element 914 formed from a material suitable to form a tight sealbetween aortic filter assembly 904 and TAVI catheter 933 or othercatheter-based device as the filters fill under systolic blood pressure.

FIGS. 41A-B depicts an aortic filter assembly 904 having an inflatableportion 927 defining a distal opening 912 of aortic filter 906. In someembodiments, inflatable portion 927 forms a continuous ring. Inflatableportion 927 forms a seal against the vessel wall such that debris cannotpass between aortic filter assembly 904 and the vessel wall. Inflatableportion 927 may also form a seal against a TAVI catheter passed betweenaortic filter assembly 904 and the vessel wall.

As depicted in FIG. 41A, inflatable portion 927 and filter element 906may form a channel 929 on an exterior surface of aortic filter assembly904 through which a catheter-based device may pass. Channel 929 forms aseal against the catheter such that debris may not flow between theaortic filter assembly 904 and the catheter.

FIG. 41B illustrates an inflatable portion 927 having a gap 931 throughwhich a catheter-based device may pass. Filter element 906 may also forma channel on the exterior surface of the aortic filter assembly 904through which the catheter may pass.

In an embodiment which includes an inflatable annulus or other support,the inflatable support is placed in fluid communication with a source ofinflation media by way of an inflation lumen extending throughout thelongitudinal length of the catheter shaft. Once the filter has beenpositioned at a desired site, the annulus can be inflated by injectionof any of a variety of inflation media, such as saline. The inflationmedia may thereafter be aspirated from the filter support, to enablecollapse and withdraw of the filter. The inflation media may include aradiopaque dye to help the operator locate the inflatable annulus underfluoroscopy.

Although the filter systems described above were discussed in connectionwith a single filter system, the filter designs may also be used inconnection with a dual filter system.

FIG. 42 depicts one embodiment of a filter assembly that may be used inconnection with any filter-based device, including the dual filter andsingle filter systems described above. Filter assembly 926 may comprisea filter membrane 936, a filter frame element 928, and at least oneradiopaque marker. Filter membrane may 936 may be constructed from apolyurethane film or any other polymer or material exhibiting suitableproperties. In some embodiments, a laser or other mechanism may be usedto create at least one filter hole in the filter membrane through whichblood may flow. The at least one filter hole is small enough such that ablood clot or piece of embolic debris exceeding a predetermineddimension cannot pass through. The filter membrane may be formed into aconical or other shape by heat sealing a first edge of the filtermembrane to a second edge of the filter membrane, although other methodsmay be used to join a first edge of the filter membrane to a second edgeof the filter membrane. In several embodiments, filter assembly 926 mayalso include flexible coupler 922.

A frame element 928 may be shaped from a Nitinol wire, but, as discussedin earlier paragraphs, the frame element may be shaped from any othersuitable material or textured to exhibit desired properties. In someembodiments, at least one radiopaque marker is incorporated into filterassembly 926. In one embodiment, a 90/10 platinum/iridium coil marker ispositioned around frame element 928 and bonded with an adhesive.Alternatively, other types of radiopaque markers may be integrated intoor affixed to frame element 928. Other methods of affixing theradiopaque marker may also be used.

In several embodiments, filter assembly 926 includes a strut tubing 924.Strut tubing 924 may be constructed from PET heat shrink tube, polyimidetube, or any other material exhibiting suitable properties. In oneembodiment, strut tubing 924 is affixed to one or more legs of frameelement 928 with an adhesive, although other means for affixation mayalso be used. Additional mechanisms may also be used to reinforce theadhesive or other means of affixation. Alternatively, strut tube 924 maybe slipped over one or more portions of the frame element 928 and mayadditionally be bonded in place.

In some embodiments, filter membrane 936 may be attached to frameelement 928 by heat-sealing a first portion of filter membrane 936 to asecond portion of filter membrane 936 to form a sleeve through whichframe element 928 may pass. An adhesive may be used to reinforce thebond between the frame element and the filter membrane. Other mechanismsmay also be used to affix frame element 928 to filter membrane 936.Additional mechanisms may also be used to reinforce the adhesive orother affixation mechanism.

In some embodiments, frame element 928 is attached to a filter shaft 920via a stainless steel crimp 998, although other mechanisms may be usedto affix frame element 928 to a filter shaft 920. Additional affixationmethods may also be used to reinforce the stainless steel crimp 998 orother mechanism.

In several embodiments, a cannulated distal tip 940 having an atraumaticdistal end with a guidewire exit port is joined to the distal end offilter shaft 920.

FIG. 43 illustrates a proximal portion of an exemplary filter system.The portion shown in FIG. 43 is generally the portion of the system thatremains external to the subject and is used to control the delivery andactuation of system components. Proximal sheath 1010 is fixedly coupledto proximal sheath hub 1012, which when advanced distally will sheaththe proximal filter (as described herein), and when retracted proximallywill allow the proximal filter to expand. The actuation, or control,portion also includes handle 1016, which is secured to proximal shaft1014. When handle 1016 is maintained axially in position, the positionof the proximal filter is axially maintained. The actuation portion alsoincludes distal sheath actuator 1022, which includes handle 1023 anddeflection control 1020. Distal sheath actuator 1022 is secured todistal shaft 1018. As described herein, the distal articulating sheathis adapted to have three independent degrees of motion relative to theproximal sheath and proximal filter: rotation, axially translation(i.e., proximal and distal), and deflection, and distal sheath actuator1022 is adapted to move distal sheath 1018 in the three degrees ofmotion. Distal sheath 1018 is rotated in the direction shown in FIG. 43by rotating distal sheath actuator 1022. Axial translation of distalsheath occurs by advancing actuator 1022 distally (pushing) or byretracting actuator 1022 proximally (pulling). Distal sheath 218 isdeflected by axial movement of deflection control 1020. Movement ofdeflection control 1020 actuates the pull wire(s) within distal sheath1018 to control the bending of distal sheath 1018. Also shown is guidingmember 1024, which is secured to the distal filter and is axiallymovable relative to the distal sheath to deploy and collapse the distalfilter as described herein. The control portion also includes hemostasisvalves 1026, which in this embodiment are rotating.

FIG. 44 illustrates an exemplary 2-piece handle design that can be usedwith any of the filter systems described herein. This 2-piece handledesign includes distal sheath actuator 1046, which includes handlesection 1048 and deflection control knob 1050. Deflection control knob1050 of distal sheath actuator 1046 is secured to distal shaft 1054.Axial movement of distal sheath actuator 1046 will translate distalshaft 1054 either distally or proximally relative to the proximal filterand proximal sheath. A pull wire (not shown in FIG. 44) is secured tohandle section 1048 and to the distal articulatable sheath (not shown inFIG. 44). Axial movement of deflection control knob 1050 appliestension, or relieves tension depending on the direction of axialmovement of deflection control knob 1050, to control the deflection ofthe distal articulatable sheath relative to the proximal filter andproximal sheath 1044, which has been described herein. Rotation ofdistal sheath actuator 1046 will rotate the distal sheath relative tothe proximal filter and proximal sheath. The handle also includeshousing 1040, in which proximal sheath hub 1042 is disposed. Proximalsheath hub 1042 is secured to proximal sheath 1044 and is adapted to bemoved axially to control the axial movement of proximal sheath 1044.

FIG. 45 illustrates another exemplary embodiment of a handle that can beused with any of the filter systems described herein. In this alternateembodiment the handle is of a 3-piece design. This 3-piece handle designcomprises a first proximal piece which includes distal sheath actuator1061, which includes handle section 1063 and deflection control knob1065. Deflection control knob 1065 of distal sheath actuator 1061 issecured to distal shaft 1067. Axial movement of distal sheath actuator1061 will translate distal shaft 1067 either distally or proximallyrelative to the proximal filter and proximal sheath. A pull wire (notshown in FIG. 45) is secured to handle section 1063 and to the distalarticulatable sheath (not shown in FIG. 45). Axial movement ofdeflection control knob 1065 applies tension, or relieves tensiondepending on the direction of axial movement of deflection control knob1065, to control the deflection of the distal articulatable sheathrelative to the proximal filter and proximal sheath 1069. Rotation ofdistal sheath actuator 1061 will rotate the distal sheath relative tothe proximal filter and proximal sheath 1069. The handle design furtherincludes a second piece comprising central section 1060 which is securedto proximal shaft 1071. A third distal piece of this handle designincludes housing 1062. Housing 1062 is secured to proximal sheath 1069.Housing 1062 is adapted to move axially with respect to central section1060. With central section 1060 held fixed in position, axial movementof housing 1062 translates to axial movement of proximal sheath 1069relative to proximal shaft 1071. In this manner, proximal filter 1073 iseither released from the confines of proximal sheath 1069 intoexpandable engagement within the vessel or, depending on direction ofmovement of housing 1062, is collapsed back into proximal sheath 1069.

FIG. 46 depicts another embodiment of a control handle. The controlhandle has a proximal filter control 1100 and a distal filter control1102. To deploy the device, the distal shaft of the catheter is fed overa guidewire and manipulated into position in the patient's anatomy. Todeploy the proximal filter, the proximal filter sheath control 1120 iswithdrawn proximally while holding the proximal filter handle 1118stationary. The proximal filter sheath control 1120 is a slidingcontrol; however, any other control such as a rotating knob, a pivotinglever, etc. may be used to withdraw the sheath.

When the proximal filter is properly deployed, the distal filtercontained in the distal sheath is advanced distally and positioned inthe target location by advancing the distal filter control 1102 whileholding the proximal filter control 1100 stationary. During thispositioning process, the distal filter control 1102 can be advanced,retracted or rotated relative to the proximal filter control 1100, andas needed, the deflection of the distal sheath may be controlled byactuating the distal sheath deflection control 1112 relative to thedistal filter sheath handle 1110. The distal sheath deflection control1112 is a pivoting control; however, any other control such as arotating knob, a sliding knob, etc. may be used to deflect the sheath.Once the sheath containing the collapsed distal filter is positionedcorrectly, the position of the distal filter control 1102 is lockedrelative to the proximal filter control 1100 by tightening the proximalhandle hemostasis valve 1116. Next, the distal filter may be deployed byadvancing the guiding member 1108 by grasping the distal filter Luerfitting 1104 until the filter is deployed. The position and orientationof the distal filter may be adjusted by advancing, retracting orrotating the distal filter Luer fitting 1104 relative to the distalfilter sheath handle 1110. Finally, the position of the distal filtermay be fixed relative to the distal filter sheath handle 1110 bytightening the distal handle hemostasis valve 1106. To remove the deviceupon completion of the procedure, the aforementioned procedure isreversed.

FIGS. 47A through 47I illustrate cross-sections through the controlhandle illustrated in FIG. 46, taken along the section lines indicatedin FIG. 46.

FIGS. 47A-B depict cross-sectional areas of proximal filter control1100. The distal shaft 1108 is disposed through a lumen defined by thearticulating distal sheath 1114. In these figures, the articulatingdistal sheath 1114 is disposed through a lumen defined by the proximalfilter shaft 1124, and the proximal filter shaft is disposed through alumen defined by the front handle 1118.

FIG. 47C depicts a cross-sectional area of a distal section of distalfilter control 1102. In FIG. 47C, articulating distal sheath 1114 isdisposed through a lumen defined by the rear handle 1110 as shown inFIG. 47C. FIG. 47D shows a cross-sectional view proximal to thecross-section shown in FIG. 47C. In FIG. 47D, guiding member 1108 isdisposed through a lumen defined by the rear handle 1110. Guiding member1108 defines a lumen 1128 through which a guidewire may pass. FIG. 47Eshows a cross-sectional view proximal to the cross-section shown in FIG.47D. The guiding member 1108 is coaxial with a stainless steel hypotube1130. Hypotube 1130 reinforces the guiding member 1108.

FIG. 47F depicts a longitudinal cross-section of proximal filter control1100. At the distal end of proximal filter control 1100, there is a nosepiece 1132 holding the front handle 1118 together. Proximal to nosepiece 1132 there is a proximal filter sheath control 1120 to actuate theproximal filter sheath and deploy the proximal filter. The proximalfilter sheath control is associated with a locking mechanism 1126 toprevent unintentional filter deployment and to actuate a sealingmechanism to prevent blood leakage. The locking mechanism 1126 comprisesa locking element 1134, an elastomeric seal 1138, a spring 1136, and anut 1140 for holding locking mechanism 1126 together. In certainembodiments, squeezing the proximal filter sheath control 1120 willrelease the locking element 1134 between the proximal sheath 1122 andproximal filter shaft 1124.

FIGS. 47G-H depicts a longitudinal cross section of distal filtercontrol 1102. At a distal section of the distal filter control 1102,there is a mechanism to actuate articulating distal sheath 1114. Theactuation mechanism includes an axially movable deflection lever 1112pivoting on distal sheath pivot 1146. The distal sheath deflection lever1112 is connected to the distal sheath pull wire at attachment point1150. The pull wire is disposed through channel 1148. Proximal to rearhandle 1110 there is a distal handle hemostasis valve 1106. Distalhandle hemostasis valve 1106 comprises elastomeric seal 1152 and HV nut1154. Distal filter shaft 1108 and hypotube 1130 extend proximally fromdistal filter control 1102 and terminate at distal filter luer lockfitting 1104.

An alternative control handle uses a rotating screw drive mechanism todeflect a distal end of a distal articulating sheath is shown in FIG.48. In certain clinical scenarios, it may be desirable to include amechanism that prevents the articulating sheath from unintentionallydeflecting when the operator releases the handle. The mechanismincorporates a lead screw 1214 which is inherently self-locking in thattip deflection will be locked wherever the handle control is released bythe operator. A rotating screw drive mechanism provides an easy tomanufacture design to control the pivot of the articulating sheath. Therate of deflection of the tip is controlled by the pitch of the screwthreads 1218, thus rapid deflection of the tip, which can lead tounintentional vessel damage, can be prevented.

While specific embodiments have been described herein, it will beobvious to those skilled in the art that such embodiments are providedby way of example only. Numerous variations, changes, and substitutionswill now occur to those skilled in the art without departing from thatwhich is disclosed. It should be understood that various alternatives tothe embodiments described herein may be employed in practicing thedisclosure.

1-5. (canceled)
 6. An intravascular filter, comprising: a proximalsheath; a proximal shaft extending through the proximal sheath; anexpandable proximal filter carried by the proximal shaft and collapsedwithin the proximal sheath; an articulable distal sheath extendingthrough the proximal shaft, the articulable distal sheath having anarticulation zone comprising a pull wire, wherein proximal retraction ofthe pull wire causes the articulation zone to articulate; an elongate,flexible tubular body, having a proximal end and a distal end, and aguidewire lumen extending therethrough, the elongate flexible tubularbody extending through the articulable sheath; a filter frame comprisinga loop and a strut; the loop residing in a plane that intersects thetubular body at a non normal angle, and the strut connecting the loop tothe tubular body; a filter membrane extending from the loop in a distaldirection to a point of attachment to the tubular body; and a flex zoneon the tubular body positioned proximal to the filter membrane, the flexzone having a different flexibility than proximal and distal adjacentportions of the tubular body and wherein the guidewire lumen extendsthrough the flex zone.
 7. The intravascular filter as in claim 6,wherein the flex zone comprises at least one slot in the tubular body.8. The intravascular filter as in claim 6, wherein the membranecomprises a polymer.
 9. The intravascular filter as in claim 6, whereinthe flex zone comprises a flexible coupler.
 10. The intravascular filteras in claim 9, wherein the flexible coupler comprises at least one slotin the tubular body.
 11. The intravascular filter as in claim 9, whereinthe flexible coupler comprises a separate component spliced into a gapalong the tubular body.
 12. The intravascular filter as in claim 9,wherein the flexible coupler is integrally formed with the tubular body.13. The intravascular filter as in claim 9, wherein the flexible coupleris thinner than the tubular body
 14. The intravascular filter as inclaim 6, wherein the flex zone has a thinner wall than the proximal anddistal adjacent portions of the tubular body.